addr.c

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/*
 * 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/slab.h>
#include <linux/workqueue.h>
#include <linux/module.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)
{
    dev_addr->dev_type = dev->type;
    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->bound_dev_if = dev->ifindex;
    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;

    if (dev_addr->bound_dev_if) {
        dev = dev_get_by_index(&init_net, dev_addr->bound_dev_if);
        if (!dev)
            return -ENODEV;
        ret = rdma_copy_addr(dev_addr, dev, NULL);
        dev_put(dev);
        return ret;
    }

    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;

#if IS_ENABLED(CONFIG_IPV6)
    case AF_INET6:
        rcu_read_lock();
        for_each_netdev_rcu(&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;
            }
        }
        rcu_read_unlock();
        break;
#endif
    }
    return ret;
}
EXPORT_SYMBOL(rdma_translate_ip);

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

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

    mod_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 int dst_fetch_ha(struct dst_entry *dst, struct rdma_dev_addr *dev_addr, void *daddr)
{
    struct neighbour *n;
    int ret;

    n = dst_neigh_lookup(dst, daddr);

    rcu_read_lock();
    if (!n || !(n->nud_state & NUD_VALID)) {
        if (n)
            neigh_event_send(n, NULL);
        ret = -ENODATA;
    } else {
        ret = rdma_copy_addr(dev_addr, dst->dev, n->ha);
    }
    rcu_read_unlock();

    if (n)
        neigh_release(n);

    return ret;
}

static int addr4_resolve(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 rtable *rt;
    struct flowi4 fl4;
    int ret;

    memset(&fl4, 0, sizeof(fl4));
    fl4.daddr = dst_ip;
    fl4.saddr = src_ip;
    fl4.flowi4_oif = addr->bound_dev_if;
    rt = ip_route_output_key(&init_net, &fl4);
    if (IS_ERR(rt)) {
        ret = PTR_ERR(rt);
        goto out;
    }
    src_in->sin_family = AF_INET;
    src_in->sin_addr.s_addr = fl4.saddr;

    if (rt->dst.dev->flags & IFF_LOOPBACK) {
        ret = rdma_translate_ip((struct sockaddr *) dst_in, addr);
        if (!ret)
            memcpy(addr->dst_dev_addr, addr->src_dev_addr, MAX_ADDR_LEN);
        goto put;
    }

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

    ret = dst_fetch_ha(&rt->dst, addr, &fl4.daddr);
put:
    ip_rt_put(rt);
out:
    return ret;
}

#if IS_ENABLED(CONFIG_IPV6)
static int addr6_resolve(struct sockaddr_in6 *src_in,
             struct sockaddr_in6 *dst_in,
             struct rdma_dev_addr *addr)
{
    struct flowi6 fl6;
    struct dst_entry *dst;
    int ret;

    memset(&fl6, 0, sizeof fl6);
    fl6.daddr = dst_in->sin6_addr;
    fl6.saddr = src_in->sin6_addr;
    fl6.flowi6_oif = addr->bound_dev_if;

    dst = ip6_route_output(&init_net, NULL, &fl6);
    if ((ret = dst->error))
        goto put;

    if (ipv6_addr_any(&fl6.saddr)) {
        ret = ipv6_dev_get_saddr(&init_net, ip6_dst_idev(dst)->dev,
                     &fl6.daddr, 0, &fl6.saddr);
        if (ret)
            goto put;

        src_in->sin6_family = AF_INET6;
        src_in->sin6_addr = fl6.saddr;
    }

    if (dst->dev->flags & IFF_LOOPBACK) {
        ret = rdma_translate_ip((struct sockaddr *) dst_in, addr);
        if (!ret)
            memcpy(addr->dst_dev_addr, addr->src_dev_addr, MAX_ADDR_LEN);
        goto put;
    }

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

    ret = dst_fetch_ha(dst, addr, &fl6.daddr);
put:
    dst_release(dst);
    return ret;
}
#else
static int addr6_resolve(struct sockaddr_in6 *src_in,
             struct sockaddr_in6 *dst_in,
             struct rdma_dev_addr *addr)
{
    return -EADDRNOTAVAIL;
}
#endif

static int addr_resolve(struct sockaddr *src_in,
            struct sockaddr *dst_in,
            struct rdma_dev_addr *addr)
{
    if (src_in->sa_family == AF_INET) {
        return addr4_resolve((struct sockaddr_in *) src_in,
            (struct sockaddr_in *) dst_in, addr);
    } else
        return addr6_resolve((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(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);
    }
}

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;

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

    if (src_addr) {
        if (src_addr->sa_family != dst_addr->sa_family) {
            ret = -EINVAL;
            goto err;
        }

        memcpy(src_in, src_addr, ip_addr_size(src_addr));
    } else {
        src_in->sa_family = dst_addr->sa_family;
    }

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

    req->status = addr_resolve(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);
        break;
    default:
        ret = req->status;
        atomic_dec(&client->refcount);
        goto err;
    }
    return ret;
err:
    kfree(req);
    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 __init addr_init(void)
{
    addr_wq = create_singlethread_workqueue("ib_addr");
    if (!addr_wq)
        return -ENOMEM;

    register_netevent_notifier(&nb);
    return 0;
}

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

module_init(addr_init);
module_exit(addr_cleanup);