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addr.c

/*
 * 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 licensed under one of the following licenses:
 *
 * 1) under the terms of the "Common Public License 1.0" a copy of which is
 *    available from the Open Source Initiative, see
 *    http://www.opensource.org/licenses/cpl.php.
 *
 * 2) under the terms of the "The BSD License" a copy of which is
 *    available from the Open Source Initiative, see
 *    http://www.opensource.org/licenses/bsd-license.php.
 *
 * 3) under the terms of the "GNU General Public License (GPL) Version 2" a
 *    copy of which is available from the Open Source Initiative, see
 *    http://www.opensource.org/licenses/gpl-license.php.
 *
 * Licensee has the right to choose one of the above licenses.
 *
 * Redistributions of source code must retain the above copyright
 * notice and one of the license notices.
 *
 * Redistributions in binary form must reproduce both the above copyright
 * notice, one of the license notices in the documentation
 * and/or other materials provided with the distribution.
 */

#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 <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 src_addr;
      struct sockaddr 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);
      return 0;
}
EXPORT_SYMBOL(rdma_copy_addr);

int rdma_translate_ip(struct sockaddr *addr, struct rdma_dev_addr *dev_addr)
{
      struct net_device *dev;
      __be32 ip = ((struct sockaddr_in *) addr)->sin_addr.s_addr;
      int ret;

      dev = ip_dev_find(ip);
      if (!dev)
            return -EADDRNOTAVAIL;

      ret = rdma_copy_addr(dev_addr, dev, NULL);
      dev_put(dev);
      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_in *dst_in)
{
      struct rtable *rt;
      struct flowi fl;
      u32 dst_ip = dst_in->sin_addr.s_addr;

      memset(&fl, 0, sizeof fl);
      fl.nl_u.ip4_u.daddr = dst_ip;
      if (ip_route_output_key(&rt, &fl))
            return;

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

static int addr_resolve_remote(struct sockaddr_in *src_in,
                         struct sockaddr_in *dst_in,
                         struct rdma_dev_addr *addr)
{
      u32 src_ip = src_in->sin_addr.s_addr;
      u32 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(&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 void process_req(struct work_struct *work)
{
      struct addr_req *req, *temp_req;
      struct sockaddr_in *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_in *) &req->src_addr;
                  dst_in = (struct sockaddr_in *) &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, &req->src_addr, req->addr,
                        req->context);
            put_client(req->client);
            kfree(req);
      }
}

static int addr_resolve_local(struct sockaddr_in *src_in,
                        struct sockaddr_in *dst_in,
                        struct rdma_dev_addr *addr)
{
      struct net_device *dev;
      u32 src_ip = src_in->sin_addr.s_addr;
      __be32 dst_ip = dst_in->sin_addr.s_addr;
      int ret;

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

      if (ZERONET(src_ip)) {
            src_in->sin_family = dst_in->sin_family;
            src_in->sin_addr.s_addr = dst_ip;
            ret = rdma_copy_addr(addr, dev, dev->dev_addr);
      } else if (LOOPBACK(src_ip)) {
            ret = rdma_translate_ip((struct sockaddr *)dst_in, addr);
            if (!ret)
                  memcpy(addr->dst_dev_addr, dev->dev_addr, MAX_ADDR_LEN);
      } else {
            ret = rdma_translate_ip((struct sockaddr *)src_in, addr);
            if (!ret)
                  memcpy(addr->dst_dev_addr, dev->dev_addr, MAX_ADDR_LEN);
      }

      dev_put(dev);
      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_in *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_in *) &req->src_addr;
      dst_in = (struct sockaddr_in *) &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);

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