drivers/infiniband/core/addr.c - maze/linux - Git at Google

 /*
  * Copyright (c) 2005 Voltaire Inc.  All rights reserved.
  * Copyright (c) 2002-2005, Network Appliance, Inc. All rights reserved.
  * Copyright (c) 1999-2005, Mellanox Technologies, Inc. All rights reserved.
  * Copyright (c) 2005 Intel Corporation.  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/mutex.h>
 #include <linux/inetdevice.h>
 #include <linux/workqueue.h>
 #include <linux/if_arp.h>
 #include <net/arp.h>
 #include <net/neighbour.h>
 #include <net/route.h>
 #include <net/netevent.h>
 #include <net/addrconf.h>
 #include <net/ip6_route.h>
 #include <rdma/ib_addr.h>

 MODULE_AUTHOR("Sean Hefty");
 MODULE_DESCRIPTION("IB Address Translation");
 MODULE_LICENSE("Dual BSD/GPL");

 struct addr_req {
 	struct list_head list;
 	struct sockaddr_storage src_addr;
 	struct sockaddr_storage dst_addr;
 	struct rdma_dev_addr *addr;
 	struct rdma_addr_client *client;
 	void *context;
 	void (*callback)(int status, struct sockaddr *src_addr,
 			 struct rdma_dev_addr *addr, void *context);
 	unsigned long timeout;
 	int status;
 };

 static void process_req(struct work_struct *work);

 static DEFINE_MUTEX(lock);
 static LIST_HEAD(req_list);
 static DECLARE_DELAYED_WORK(work, process_req);
 static struct workqueue_struct *addr_wq;

 void rdma_addr_register_client(struct rdma_addr_client *client)
 {
 	atomic_set(&client->refcount, 1);
 	init_completion(&client->comp);
 }
 EXPORT_SYMBOL(rdma_addr_register_client);

 static inline void put_client(struct rdma_addr_client *client)
 {
 	if (atomic_dec_and_test(&client->refcount))
 		complete(&client->comp);
 }

 void rdma_addr_unregister_client(struct rdma_addr_client *client)
 {
 	put_client(client);
 	wait_for_completion(&client->comp);
 }
 EXPORT_SYMBOL(rdma_addr_unregister_client);

 int rdma_copy_addr(struct rdma_dev_addr *dev_addr, struct net_device *dev,
 		     const unsigned char *dst_dev_addr)
 {
 	switch (dev->type) {
 	case ARPHRD_INFINIBAND:
 		dev_addr->dev_type = RDMA_NODE_IB_CA;
 		break;
 	case ARPHRD_ETHER:
 		dev_addr->dev_type = RDMA_NODE_RNIC;
 		break;
 	default:
 		return -EADDRNOTAVAIL;
 	}

 	memcpy(dev_addr->src_dev_addr, dev->dev_addr, MAX_ADDR_LEN);
 	memcpy(dev_addr->broadcast, dev->broadcast, MAX_ADDR_LEN);
 	if (dst_dev_addr)
 		memcpy(dev_addr->dst_dev_addr, dst_dev_addr, MAX_ADDR_LEN);
 	dev_addr->src_dev = dev;
 	return 0;
 }
 EXPORT_SYMBOL(rdma_copy_addr);

 int rdma_translate_ip(struct sockaddr *addr, struct rdma_dev_addr *dev_addr)
 {
 	struct net_device *dev;
 	int ret = -EADDRNOTAVAIL;

 	switch (addr->sa_family) {
 	case AF_INET:
 		dev = ip_dev_find(&init_net,
 			((struct sockaddr_in *) addr)->sin_addr.s_addr);

 		if (!dev)
 			return ret;

 		ret = rdma_copy_addr(dev_addr, dev, NULL);
 		dev_put(dev);
 		break;
 	case AF_INET6:
 		for_each_netdev(&init_net, dev) {
 			if (ipv6_chk_addr(&init_net,
 					  &((struct sockaddr_in6 *) addr)->sin6_addr,
 					  dev, 1)) {
 				ret = rdma_copy_addr(dev_addr, dev, NULL);
 				break;
 			}
 		}
 		break;
 	default:
 		break;
 	}
 	return ret;
 }
 EXPORT_SYMBOL(rdma_translate_ip);

 static void set_timeout(unsigned long time)
 {
 	unsigned long delay;

 	cancel_delayed_work(&work);

 	delay = time - jiffies;
 	if ((long)delay <= 0)
 		delay = 1;

 	queue_delayed_work(addr_wq, &work, delay);
 }

 static void queue_req(struct addr_req *req)
 {
 	struct addr_req *temp_req;

 	mutex_lock(&lock);
 	list_for_each_entry_reverse(temp_req, &req_list, list) {
 		if (time_after_eq(req->timeout, temp_req->timeout))
 			break;
 	}

 	list_add(&req->list, &temp_req->list);

 	if (req_list.next == &req->list)
 		set_timeout(req->timeout);
 	mutex_unlock(&lock);
 }

 static void addr_send_arp(struct sockaddr *dst_in)
 {
 	struct rtable *rt;
 	struct flowi fl;
 	struct dst_entry *dst;

 	memset(&fl, 0, sizeof fl);
 	if (dst_in->sa_family == AF_INET)  {
 		fl.nl_u.ip4_u.daddr =
 			((struct sockaddr_in *) dst_in)->sin_addr.s_addr;

 		if (ip_route_output_key(&init_net, &rt, &fl))
 			return;

 		neigh_event_send(rt->u.dst.neighbour, NULL);
 		ip_rt_put(rt);

 	} else {
 		fl.nl_u.ip6_u.daddr =
 			((struct sockaddr_in6 *) dst_in)->sin6_addr;

 		dst = ip6_route_output(&init_net, NULL, &fl);
 		if (!dst)
 			return;

 		neigh_event_send(dst->neighbour, NULL);
 		dst_release(dst);
 	}
 }

 static int addr4_resolve_remote(struct sockaddr_in *src_in,
 			       struct sockaddr_in *dst_in,
 			       struct rdma_dev_addr *addr)
 {
 	__be32 src_ip = src_in->sin_addr.s_addr;
 	__be32 dst_ip = dst_in->sin_addr.s_addr;
 	struct flowi fl;
 	struct rtable *rt;
 	struct neighbour *neigh;
 	int ret;

 	memset(&fl, 0, sizeof fl);
 	fl.nl_u.ip4_u.daddr = dst_ip;
 	fl.nl_u.ip4_u.saddr = src_ip;
 	ret = ip_route_output_key(&init_net, &rt, &fl);
 	if (ret)
 		goto out;

 	/* If the device does ARP internally, return 'done' */
 	if (rt->idev->dev->flags & IFF_NOARP) {
 		rdma_copy_addr(addr, rt->idev->dev, NULL);
 		goto put;
 	}

 	neigh = neigh_lookup(&arp_tbl, &rt->rt_gateway, rt->idev->dev);
 	if (!neigh) {
 		ret = -ENODATA;
 		goto put;
 	}

 	if (!(neigh->nud_state & NUD_VALID)) {
 		ret = -ENODATA;
 		goto release;
 	}

 	if (!src_ip) {
 		src_in->sin_family = dst_in->sin_family;
 		src_in->sin_addr.s_addr = rt->rt_src;
 	}

 	ret = rdma_copy_addr(addr, neigh->dev, neigh->ha);
 release:
 	neigh_release(neigh);
 put:
 	ip_rt_put(rt);
 out:
 	return ret;
 }

 static int addr6_resolve_remote(struct sockaddr_in6 *src_in,
 			       struct sockaddr_in6 *dst_in,
 			       struct rdma_dev_addr *addr)
 {
 	struct flowi fl;
 	struct neighbour *neigh;
 	struct dst_entry *dst;
 	int ret = -ENODATA;

 	memset(&fl, 0, sizeof fl);
 	fl.nl_u.ip6_u.daddr = dst_in->sin6_addr;
 	fl.nl_u.ip6_u.saddr = src_in->sin6_addr;

 	dst = ip6_route_output(&init_net, NULL, &fl);
 	if (!dst)
 		return ret;

 	if (dst->dev->flags & IFF_NOARP) {
 		ret = rdma_copy_addr(addr, dst->dev, NULL);
 	} else {
 		neigh = dst->neighbour;
 		if (neigh && (neigh->nud_state & NUD_VALID))
 			ret = rdma_copy_addr(addr, neigh->dev, neigh->ha);
 	}

 	dst_release(dst);
 	return ret;
 }

 static int addr_resolve_remote(struct sockaddr *src_in,
 				struct sockaddr *dst_in,
 				struct rdma_dev_addr *addr)
 {
 	if (src_in->sa_family == AF_INET) {
 		return addr4_resolve_remote((struct sockaddr_in *) src_in,
 			(struct sockaddr_in *) dst_in, addr);
 	} else
 		return addr6_resolve_remote((struct sockaddr_in6 *) src_in,
 			(struct sockaddr_in6 *) dst_in, addr);
 }

 static void process_req(struct work_struct *work)
 {
 	struct addr_req *req, *temp_req;
 	struct sockaddr *src_in, *dst_in;
 	struct list_head done_list;

 	INIT_LIST_HEAD(&done_list);

 	mutex_lock(&lock);
 	list_for_each_entry_safe(req, temp_req, &req_list, list) {
 		if (req->status == -ENODATA) {
 			src_in = (struct sockaddr *) &req->src_addr;
 			dst_in = (struct sockaddr *) &req->dst_addr;
 			req->status = addr_resolve_remote(src_in, dst_in,
 							  req->addr);
 			if (req->status && time_after_eq(jiffies, req->timeout))
 				req->status = -ETIMEDOUT;
 			else if (req->status == -ENODATA)
 				continue;
 		}
 		list_move_tail(&req->list, &done_list);
 	}

 	if (!list_empty(&req_list)) {
 		req = list_entry(req_list.next, struct addr_req, list);
 		set_timeout(req->timeout);
 	}
 	mutex_unlock(&lock);

 	list_for_each_entry_safe(req, temp_req, &done_list, list) {
 		list_del(&req->list);
 		req->callback(req->status, (struct sockaddr *) &req->src_addr,
 			req->addr, req->context);
 		put_client(req->client);
 		kfree(req);
 	}
 }

 static int addr_resolve_local(struct sockaddr *src_in,
 			      struct sockaddr *dst_in,
 			      struct rdma_dev_addr *addr)
 {
 	struct net_device *dev;
 	int ret;

 	if (dst_in->sa_family == AF_INET) {
 		__be32 src_ip = ((struct sockaddr_in *) src_in)->sin_addr.s_addr;
 		__be32 dst_ip = ((struct sockaddr_in *) dst_in)->sin_addr.s_addr;

 		dev = ip_dev_find(&init_net, dst_ip);
 		if (!dev)
 			return -EADDRNOTAVAIL;

 		if (ipv4_is_zeronet(src_ip)) {
 			src_in->sa_family = dst_in->sa_family;
 			((struct sockaddr_in *) src_in)->sin_addr.s_addr = dst_ip;
 			ret = rdma_copy_addr(addr, dev, dev->dev_addr);
 		} else if (ipv4_is_loopback(src_ip)) {
 			ret = rdma_translate_ip(dst_in, addr);
 			if (!ret)
 				memcpy(addr->dst_dev_addr, dev->dev_addr, MAX_ADDR_LEN);
 		} else {
 			ret = rdma_translate_ip(src_in, addr);
 			if (!ret)
 				memcpy(addr->dst_dev_addr, dev->dev_addr, MAX_ADDR_LEN);
 		}
 		dev_put(dev);
 	} else {
 		struct in6_addr *a;

 		for_each_netdev(&init_net, dev)
 			if (ipv6_chk_addr(&init_net,
 					  &((struct sockaddr_in6 *) addr)->sin6_addr,
 					  dev, 1))
 				break;

 		if (!dev)
 			return -EADDRNOTAVAIL;

 		a = &((struct sockaddr_in6 *) src_in)->sin6_addr;

 		if (ipv6_addr_any(a)) {
 			src_in->sa_family = dst_in->sa_family;
 			((struct sockaddr_in6 *) src_in)->sin6_addr =
 				((struct sockaddr_in6 *) dst_in)->sin6_addr;
 			ret = rdma_copy_addr(addr, dev, dev->dev_addr);
 		} else if (ipv6_addr_loopback(a)) {
 			ret = rdma_translate_ip(dst_in, addr);
 			if (!ret)
 				memcpy(addr->dst_dev_addr, dev->dev_addr, MAX_ADDR_LEN);
 		} else  {
 			ret = rdma_translate_ip(src_in, addr);
 			if (!ret)
 				memcpy(addr->dst_dev_addr, dev->dev_addr, MAX_ADDR_LEN);
 		}
 	}

 	return ret;
 }

 int rdma_resolve_ip(struct rdma_addr_client *client,
 		    struct sockaddr *src_addr, struct sockaddr *dst_addr,
 		    struct rdma_dev_addr *addr, int timeout_ms,
 		    void (*callback)(int status, struct sockaddr *src_addr,
 				     struct rdma_dev_addr *addr, void *context),
 		    void *context)
 {
 	struct sockaddr *src_in, *dst_in;
 	struct addr_req *req;
 	int ret = 0;

 	req = kzalloc(sizeof *req, GFP_KERNEL);
 	if (!req)
 		return -ENOMEM;

 	if (src_addr)
 		memcpy(&req->src_addr, src_addr, ip_addr_size(src_addr));
 	memcpy(&req->dst_addr, dst_addr, ip_addr_size(dst_addr));
 	req->addr = addr;
 	req->callback = callback;
 	req->context = context;
 	req->client = client;
 	atomic_inc(&client->refcount);

 	src_in = (struct sockaddr *) &req->src_addr;
 	dst_in = (struct sockaddr *) &req->dst_addr;

 	req->status = addr_resolve_local(src_in, dst_in, addr);
 	if (req->status == -EADDRNOTAVAIL)
 		req->status = addr_resolve_remote(src_in, dst_in, addr);

 	switch (req->status) {
 	case 0:
 		req->timeout = jiffies;
 		queue_req(req);
 		break;
 	case -ENODATA:
 		req->timeout = msecs_to_jiffies(timeout_ms) + jiffies;
 		queue_req(req);
 		addr_send_arp(dst_in);
 		break;
 	default:
 		ret = req->status;
 		atomic_dec(&client->refcount);
 		kfree(req);
 		break;
 	}
 	return ret;
 }
 EXPORT_SYMBOL(rdma_resolve_ip);

 void rdma_addr_cancel(struct rdma_dev_addr *addr)
 {
 	struct addr_req *req, *temp_req;

 	mutex_lock(&lock);
 	list_for_each_entry_safe(req, temp_req, &req_list, list) {
 		if (req->addr == addr) {
 			req->status = -ECANCELED;
 			req->timeout = jiffies;
 			list_move(&req->list, &req_list);
 			set_timeout(req->timeout);
 			break;
 		}
 	}
 	mutex_unlock(&lock);
 }
 EXPORT_SYMBOL(rdma_addr_cancel);

 static int netevent_callback(struct notifier_block *self, unsigned long event,
 	void *ctx)
 {
 	if (event == NETEVENT_NEIGH_UPDATE) {
 		struct neighbour *neigh = ctx;

 		if (neigh->nud_state & NUD_VALID) {
 			set_timeout(jiffies);
 		}
 	}
 	return 0;
 }

 static struct notifier_block nb = {
 	.notifier_call = netevent_callback
 };

 static int addr_init(void)
 {
 	addr_wq = create_singlethread_workqueue("ib_addr");
 	if (!addr_wq)
 		return -ENOMEM;

 	register_netevent_notifier(&nb);
 	return 0;
 }

 static void addr_cleanup(void)
 {
 	unregister_netevent_notifier(&nb);
 	destroy_workqueue(addr_wq);
 }

 module_init(addr_init);
 module_exit(addr_cleanup);
	/*
	* Copyright (c) 2005 Voltaire Inc. All rights reserved.
	* Copyright (c) 2002-2005, Network Appliance, Inc. All rights reserved.
	* Copyright (c) 1999-2005, Mellanox Technologies, Inc. All rights reserved.
	* Copyright (c) 2005 Intel Corporation. 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/mutex.h>
	#include <linux/inetdevice.h>
	#include <linux/workqueue.h>
	#include <linux/if_arp.h>
	#include <net/arp.h>
	#include <net/neighbour.h>
	#include <net/route.h>
	#include <net/netevent.h>
	#include <net/addrconf.h>
	#include <net/ip6_route.h>
	#include <rdma/ib_addr.h>

	MODULE_AUTHOR("Sean Hefty");
	MODULE_DESCRIPTION("IB Address Translation");
	MODULE_LICENSE("Dual BSD/GPL");

	struct addr_req {
	struct list_head list;
	struct sockaddr_storage src_addr;
	struct sockaddr_storage dst_addr;
	struct rdma_dev_addr *addr;
	struct rdma_addr_client *client;
	void *context;
	void (callback)(int status, struct sockaddr src_addr,
	struct rdma_dev_addr addr, void context);
	unsigned long timeout;
	int status;
	};

	static void process_req(struct work_struct *work);

	static DEFINE_MUTEX(lock);
	static LIST_HEAD(req_list);
	static DECLARE_DELAYED_WORK(work, process_req);
	static struct workqueue_struct *addr_wq;

	void rdma_addr_register_client(struct rdma_addr_client *client)
	{
	atomic_set(&client->refcount, 1);
	init_completion(&client->comp);
	}
	EXPORT_SYMBOL(rdma_addr_register_client);

	static inline void put_client(struct rdma_addr_client *client)
	{
	if (atomic_dec_and_test(&client->refcount))
	complete(&client->comp);
	}

	void rdma_addr_unregister_client(struct rdma_addr_client *client)
	{
	put_client(client);
	wait_for_completion(&client->comp);
	}
	EXPORT_SYMBOL(rdma_addr_unregister_client);

	int rdma_copy_addr(struct rdma_dev_addr dev_addr, struct net_device dev,
	const unsigned char *dst_dev_addr)
	{
	switch (dev->type) {
	case ARPHRD_INFINIBAND:
	dev_addr->dev_type = RDMA_NODE_IB_CA;
	break;
	case ARPHRD_ETHER:
	dev_addr->dev_type = RDMA_NODE_RNIC;
	break;
	default:
	return -EADDRNOTAVAIL;
	}

	memcpy(dev_addr->src_dev_addr, dev->dev_addr, MAX_ADDR_LEN);
	memcpy(dev_addr->broadcast, dev->broadcast, MAX_ADDR_LEN);
	if (dst_dev_addr)
	memcpy(dev_addr->dst_dev_addr, dst_dev_addr, MAX_ADDR_LEN);
	dev_addr->src_dev = dev;
	return 0;
	}
	EXPORT_SYMBOL(rdma_copy_addr);

	int rdma_translate_ip(struct sockaddr addr, struct rdma_dev_addr dev_addr)
	{
	struct net_device *dev;
	int ret = -EADDRNOTAVAIL;

	switch (addr->sa_family) {
	case AF_INET:
	dev = ip_dev_find(&init_net,
	((struct sockaddr_in *) addr)->sin_addr.s_addr);

	if (!dev)
	return ret;

	ret = rdma_copy_addr(dev_addr, dev, NULL);
	dev_put(dev);
	break;
	case AF_INET6:
	for_each_netdev(&init_net, dev) {
	if (ipv6_chk_addr(&init_net,
	&((struct sockaddr_in6 *) addr)->sin6_addr,
	dev, 1)) {
	ret = rdma_copy_addr(dev_addr, dev, NULL);
	break;
	}
	}
	break;
	default:
	break;
	}
	return ret;
	}
	EXPORT_SYMBOL(rdma_translate_ip);

	static void set_timeout(unsigned long time)
	{
	unsigned long delay;

	cancel_delayed_work(&work);

	delay = time - jiffies;
	if ((long)delay <= 0)
	delay = 1;

	queue_delayed_work(addr_wq, &work, delay);
	}

	static void queue_req(struct addr_req *req)
	{
	struct addr_req *temp_req;

	mutex_lock(&lock);
	list_for_each_entry_reverse(temp_req, &req_list, list) {
	if (time_after_eq(req->timeout, temp_req->timeout))
	break;
	}

	list_add(&req->list, &temp_req->list);

	if (req_list.next == &req->list)
	set_timeout(req->timeout);
	mutex_unlock(&lock);
	}

	static void addr_send_arp(struct sockaddr *dst_in)
	{
	struct rtable *rt;
	struct flowi fl;
	struct dst_entry *dst;

	memset(&fl, 0, sizeof fl);
	if (dst_in->sa_family == AF_INET) {
	fl.nl_u.ip4_u.daddr =
	((struct sockaddr_in *) dst_in)->sin_addr.s_addr;

	if (ip_route_output_key(&init_net, &rt, &fl))
	return;

	neigh_event_send(rt->u.dst.neighbour, NULL);
	ip_rt_put(rt);

	} else {
	fl.nl_u.ip6_u.daddr =
	((struct sockaddr_in6 *) dst_in)->sin6_addr;

	dst = ip6_route_output(&init_net, NULL, &fl);
	if (!dst)
	return;

	neigh_event_send(dst->neighbour, NULL);
	dst_release(dst);
	}
	}

	static int addr4_resolve_remote(struct sockaddr_in *src_in,
	struct sockaddr_in *dst_in,
	struct rdma_dev_addr *addr)
	{
	__be32 src_ip = src_in->sin_addr.s_addr;
	__be32 dst_ip = dst_in->sin_addr.s_addr;
	struct flowi fl;
	struct rtable *rt;
	struct neighbour *neigh;
	int ret;

	memset(&fl, 0, sizeof fl);
	fl.nl_u.ip4_u.daddr = dst_ip;
	fl.nl_u.ip4_u.saddr = src_ip;
	ret = ip_route_output_key(&init_net, &rt, &fl);
	if (ret)
	goto out;

	/* If the device does ARP internally, return 'done' */
	if (rt->idev->dev->flags & IFF_NOARP) {
	rdma_copy_addr(addr, rt->idev->dev, NULL);
	goto put;
	}

	neigh = neigh_lookup(&arp_tbl, &rt->rt_gateway, rt->idev->dev);
	if (!neigh) {
	ret = -ENODATA;
	goto put;
	}

	if (!(neigh->nud_state & NUD_VALID)) {
	ret = -ENODATA;
	goto release;
	}

	if (!src_ip) {
	src_in->sin_family = dst_in->sin_family;
	src_in->sin_addr.s_addr = rt->rt_src;
	}

	ret = rdma_copy_addr(addr, neigh->dev, neigh->ha);
	release:
	neigh_release(neigh);
	put:
	ip_rt_put(rt);
	out:
	return ret;
	}

	static int addr6_resolve_remote(struct sockaddr_in6 *src_in,
	struct sockaddr_in6 *dst_in,
	struct rdma_dev_addr *addr)
	{
	struct flowi fl;
	struct neighbour *neigh;
	struct dst_entry *dst;
	int ret = -ENODATA;

	memset(&fl, 0, sizeof fl);
	fl.nl_u.ip6_u.daddr = dst_in->sin6_addr;
	fl.nl_u.ip6_u.saddr = src_in->sin6_addr;

	dst = ip6_route_output(&init_net, NULL, &fl);
	if (!dst)
	return ret;

	if (dst->dev->flags & IFF_NOARP) {
	ret = rdma_copy_addr(addr, dst->dev, NULL);
	} else {
	neigh = dst->neighbour;
	if (neigh && (neigh->nud_state & NUD_VALID))
	ret = rdma_copy_addr(addr, neigh->dev, neigh->ha);
	}

	dst_release(dst);
	return ret;
	}

	static int addr_resolve_remote(struct sockaddr *src_in,
	struct sockaddr *dst_in,
	struct rdma_dev_addr *addr)
	{
	if (src_in->sa_family == AF_INET) {
	return addr4_resolve_remote((struct sockaddr_in *) src_in,
	(struct sockaddr_in *) dst_in, addr);
	} else
	return addr6_resolve_remote((struct sockaddr_in6 *) src_in,
	(struct sockaddr_in6 *) dst_in, addr);
	}

	static void process_req(struct work_struct *work)
	{
	struct addr_req req, temp_req;
	struct sockaddr src_in, dst_in;
	struct list_head done_list;

	INIT_LIST_HEAD(&done_list);

	mutex_lock(&lock);
	list_for_each_entry_safe(req, temp_req, &req_list, list) {
	if (req->status == -ENODATA) {
	src_in = (struct sockaddr *) &req->src_addr;
	dst_in = (struct sockaddr *) &req->dst_addr;
	req->status = addr_resolve_remote(src_in, dst_in,
	req->addr);
	if (req->status && time_after_eq(jiffies, req->timeout))
	req->status = -ETIMEDOUT;
	else if (req->status == -ENODATA)
	continue;
	}
	list_move_tail(&req->list, &done_list);
	}

	if (!list_empty(&req_list)) {
	req = list_entry(req_list.next, struct addr_req, list);
	set_timeout(req->timeout);
	}
	mutex_unlock(&lock);

	list_for_each_entry_safe(req, temp_req, &done_list, list) {
	list_del(&req->list);
	req->callback(req->status, (struct sockaddr *) &req->src_addr,
	req->addr, req->context);
	put_client(req->client);
	kfree(req);
	}
	}

	static int addr_resolve_local(struct sockaddr *src_in,
	struct sockaddr *dst_in,
	struct rdma_dev_addr *addr)
	{
	struct net_device *dev;
	int ret;

	if (dst_in->sa_family == AF_INET) {
	__be32 src_ip = ((struct sockaddr_in *) src_in)->sin_addr.s_addr;
	__be32 dst_ip = ((struct sockaddr_in *) dst_in)->sin_addr.s_addr;

	dev = ip_dev_find(&init_net, dst_ip);
	if (!dev)
	return -EADDRNOTAVAIL;

	if (ipv4_is_zeronet(src_ip)) {
	src_in->sa_family = dst_in->sa_family;
	((struct sockaddr_in *) src_in)->sin_addr.s_addr = dst_ip;
	ret = rdma_copy_addr(addr, dev, dev->dev_addr);
	} else if (ipv4_is_loopback(src_ip)) {
	ret = rdma_translate_ip(dst_in, addr);
	if (!ret)
	memcpy(addr->dst_dev_addr, dev->dev_addr, MAX_ADDR_LEN);
	} else {
	ret = rdma_translate_ip(src_in, addr);
	if (!ret)
	memcpy(addr->dst_dev_addr, dev->dev_addr, MAX_ADDR_LEN);
	}
	dev_put(dev);
	} else {
	struct in6_addr *a;

	for_each_netdev(&init_net, dev)
	if (ipv6_chk_addr(&init_net,
	&((struct sockaddr_in6 *) addr)->sin6_addr,
	dev, 1))
	break;

	if (!dev)
	return -EADDRNOTAVAIL;

	a = &((struct sockaddr_in6 *) src_in)->sin6_addr;

	if (ipv6_addr_any(a)) {
	src_in->sa_family = dst_in->sa_family;
	((struct sockaddr_in6 *) src_in)->sin6_addr =
	((struct sockaddr_in6 *) dst_in)->sin6_addr;
	ret = rdma_copy_addr(addr, dev, dev->dev_addr);
	} else if (ipv6_addr_loopback(a)) {
	ret = rdma_translate_ip(dst_in, addr);
	if (!ret)
	memcpy(addr->dst_dev_addr, dev->dev_addr, MAX_ADDR_LEN);
	} else {
	ret = rdma_translate_ip(src_in, addr);
	if (!ret)
	memcpy(addr->dst_dev_addr, dev->dev_addr, MAX_ADDR_LEN);
	}
	}

	return ret;
	}

	int rdma_resolve_ip(struct rdma_addr_client *client,
	struct sockaddr src_addr, struct sockaddr dst_addr,
	struct rdma_dev_addr *addr, int timeout_ms,
	void (callback)(int status, struct sockaddr src_addr,
	struct rdma_dev_addr addr, void context),
	void *context)
	{
	struct sockaddr src_in, dst_in;
	struct addr_req *req;
	int ret = 0;

	req = kzalloc(sizeof *req, GFP_KERNEL);
	if (!req)
	return -ENOMEM;

	if (src_addr)
	memcpy(&req->src_addr, src_addr, ip_addr_size(src_addr));
	memcpy(&req->dst_addr, dst_addr, ip_addr_size(dst_addr));
	req->addr = addr;
	req->callback = callback;
	req->context = context;
	req->client = client;
	atomic_inc(&client->refcount);

	src_in = (struct sockaddr *) &req->src_addr;
	dst_in = (struct sockaddr *) &req->dst_addr;

	req->status = addr_resolve_local(src_in, dst_in, addr);
	if (req->status == -EADDRNOTAVAIL)
	req->status = addr_resolve_remote(src_in, dst_in, addr);

	switch (req->status) {
	case 0:
	req->timeout = jiffies;
	queue_req(req);
	break;
	case -ENODATA:
	req->timeout = msecs_to_jiffies(timeout_ms) + jiffies;
	queue_req(req);
	addr_send_arp(dst_in);
	break;
	default:
	ret = req->status;
	atomic_dec(&client->refcount);
	kfree(req);
	break;
	}
	return ret;
	}
	EXPORT_SYMBOL(rdma_resolve_ip);

	void rdma_addr_cancel(struct rdma_dev_addr *addr)
	{
	struct addr_req req, temp_req;

	mutex_lock(&lock);
	list_for_each_entry_safe(req, temp_req, &req_list, list) {
	if (req->addr == addr) {
	req->status = -ECANCELED;
	req->timeout = jiffies;
	list_move(&req->list, &req_list);
	set_timeout(req->timeout);
	break;
	}
	}
	mutex_unlock(&lock);
	}
	EXPORT_SYMBOL(rdma_addr_cancel);

	static int netevent_callback(struct notifier_block *self, unsigned long event,
	void *ctx)
	{
	if (event == NETEVENT_NEIGH_UPDATE) {
	struct neighbour *neigh = ctx;

	if (neigh->nud_state & NUD_VALID) {
	set_timeout(jiffies);
	}
	}
	return 0;
	}

	static struct notifier_block nb = {
	.notifier_call = netevent_callback
	};

	static int addr_init(void)
	{
	addr_wq = create_singlethread_workqueue("ib_addr");
	if (!addr_wq)
	return -ENOMEM;

	register_netevent_notifier(&nb);
	return 0;
	}

	static void addr_cleanup(void)
	{
	unregister_netevent_notifier(&nb);
	destroy_workqueue(addr_wq);
	}

	module_init(addr_init);
	module_exit(addr_cleanup);