raw.c

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/*
 * raw.c - Raw sockets for protocol family CAN
 *
 * Copyright (c) 2002-2007 Volkswagen Group Electronic Research
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 * 3. Neither the name of Volkswagen nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * Alternatively, provided that this notice is retained in full, this
 * software may be distributed under the terms of the GNU General
 * Public License ("GPL") version 2, in which case the provisions of the
 * GPL apply INSTEAD OF those given above.
 *
 * The provided data structures and external interfaces from this code
 * are not restricted to be used by modules with a GPL compatible license.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 *
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/uio.h>
#include <linux/net.h>
#include <linux/slab.h>
#include <linux/netdevice.h>
#include <linux/socket.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>
#include <linux/can.h>
#include <linux/can/core.h>
#include <linux/can/raw.h>
#include <net/sock.h>
#include <net/net_namespace.h>

#define CAN_RAW_VERSION CAN_VERSION
static __initconst const char banner[] =
    KERN_INFO "can: raw protocol (rev " CAN_RAW_VERSION ")\n";

MODULE_DESCRIPTION("PF_CAN raw protocol");
MODULE_LICENSE("Dual BSD/GPL");
MODULE_AUTHOR("Urs Thuermann <[email protected]>");
MODULE_ALIAS("can-proto-1");

#define MASK_ALL 0

/*
 * A raw socket has a list of can_filters attached to it, each receiving
 * the CAN frames matching that filter.  If the filter list is empty,
 * no CAN frames will be received by the socket.  The default after
 * opening the socket, is to have one filter which receives all frames.
 * The filter list is allocated dynamically with the exception of the
 * list containing only one item.  This common case is optimized by
 * storing the single filter in dfilter, to avoid using dynamic memory.
 */

struct raw_sock {
    struct sock sk;
    int bound;
    int ifindex;
    struct notifier_block notifier;
    int loopback;
    int recv_own_msgs;
    int fd_frames;
    int count;                 /* number of active filters */
    struct can_filter dfilter; /* default/single filter */
    struct can_filter *filter; /* pointer to filter(s) */
    can_err_mask_t err_mask;
};

/*
 * Return pointer to store the extra msg flags for raw_recvmsg().
 * We use the space of one unsigned int beyond the 'struct sockaddr_can'
 * in skb->cb.
 */
static inline unsigned int *raw_flags(struct sk_buff *skb)
{
    BUILD_BUG_ON(sizeof(skb->cb) <= (sizeof(struct sockaddr_can) +
                     sizeof(unsigned int)));

    /* return pointer after struct sockaddr_can */
    return (unsigned int *)(&((struct sockaddr_can *)skb->cb)[1]);
}

static inline struct raw_sock *raw_sk(const struct sock *sk)
{
    return (struct raw_sock *)sk;
}

static void raw_rcv(struct sk_buff *oskb, void *data)
{
    struct sock *sk = (struct sock *)data;
    struct raw_sock *ro = raw_sk(sk);
    struct sockaddr_can *addr;
    struct sk_buff *skb;
    unsigned int *pflags;

    /* check the received tx sock reference */
    if (!ro->recv_own_msgs && oskb->sk == sk)
        return;

    /* do not pass frames with DLC > 8 to a legacy socket */
    if (!ro->fd_frames) {
        struct canfd_frame *cfd = (struct canfd_frame *)oskb->data;

        if (unlikely(cfd->len > CAN_MAX_DLEN))
            return;
    }

    /* clone the given skb to be able to enqueue it into the rcv queue */
    skb = skb_clone(oskb, GFP_ATOMIC);
    if (!skb)
        return;

    /*
     *  Put the datagram to the queue so that raw_recvmsg() can
     *  get it from there.  We need to pass the interface index to
     *  raw_recvmsg().  We pass a whole struct sockaddr_can in skb->cb
     *  containing the interface index.
     */

    BUILD_BUG_ON(sizeof(skb->cb) < sizeof(struct sockaddr_can));
    addr = (struct sockaddr_can *)skb->cb;
    memset(addr, 0, sizeof(*addr));
    addr->can_family  = AF_CAN;
    addr->can_ifindex = skb->dev->ifindex;

    /* add CAN specific message flags for raw_recvmsg() */
    pflags = raw_flags(skb);
    *pflags = 0;
    if (oskb->sk)
        *pflags |= MSG_DONTROUTE;
    if (oskb->sk == sk)
        *pflags |= MSG_CONFIRM;

    if (sock_queue_rcv_skb(sk, skb) < 0)
        kfree_skb(skb);
}

static int raw_enable_filters(struct net_device *dev, struct sock *sk,
                  struct can_filter *filter, int count)
{
    int err = 0;
    int i;

    for (i = 0; i < count; i++) {
        err = can_rx_register(dev, filter[i].can_id,
                      filter[i].can_mask,
                      raw_rcv, sk, "raw");
        if (err) {
            /* clean up successfully registered filters */
            while (--i >= 0)
                can_rx_unregister(dev, filter[i].can_id,
                          filter[i].can_mask,
                          raw_rcv, sk);
            break;
        }
    }

    return err;
}

static int raw_enable_errfilter(struct net_device *dev, struct sock *sk,
                can_err_mask_t err_mask)
{
    int err = 0;

    if (err_mask)
        err = can_rx_register(dev, 0, err_mask | CAN_ERR_FLAG,
                      raw_rcv, sk, "raw");

    return err;
}

static void raw_disable_filters(struct net_device *dev, struct sock *sk,
                  struct can_filter *filter, int count)
{
    int i;

    for (i = 0; i < count; i++)
        can_rx_unregister(dev, filter[i].can_id, filter[i].can_mask,
                  raw_rcv, sk);
}

static inline void raw_disable_errfilter(struct net_device *dev,
                     struct sock *sk,
                     can_err_mask_t err_mask)

{
    if (err_mask)
        can_rx_unregister(dev, 0, err_mask | CAN_ERR_FLAG,
                  raw_rcv, sk);
}

static inline void raw_disable_allfilters(struct net_device *dev,
                      struct sock *sk)
{
    struct raw_sock *ro = raw_sk(sk);

    raw_disable_filters(dev, sk, ro->filter, ro->count);
    raw_disable_errfilter(dev, sk, ro->err_mask);
}

static int raw_enable_allfilters(struct net_device *dev, struct sock *sk)
{
    struct raw_sock *ro = raw_sk(sk);
    int err;

    err = raw_enable_filters(dev, sk, ro->filter, ro->count);
    if (!err) {
        err = raw_enable_errfilter(dev, sk, ro->err_mask);
        if (err)
            raw_disable_filters(dev, sk, ro->filter, ro->count);
    }

    return err;
}

static int raw_notifier(struct notifier_block *nb,
            unsigned long msg, void *data)
{
    struct net_device *dev = (struct net_device *)data;
    struct raw_sock *ro = container_of(nb, struct raw_sock, notifier);
    struct sock *sk = &ro->sk;

    if (!net_eq(dev_net(dev), &init_net))
        return NOTIFY_DONE;

    if (dev->type != ARPHRD_CAN)
        return NOTIFY_DONE;

    if (ro->ifindex != dev->ifindex)
        return NOTIFY_DONE;

    switch (msg) {

    case NETDEV_UNREGISTER:
        lock_sock(sk);
        /* remove current filters & unregister */
        if (ro->bound)
            raw_disable_allfilters(dev, sk);

        if (ro->count > 1)
            kfree(ro->filter);

        ro->ifindex = 0;
        ro->bound   = 0;
        ro->count   = 0;
        release_sock(sk);

        sk->sk_err = ENODEV;
        if (!sock_flag(sk, SOCK_DEAD))
            sk->sk_error_report(sk);
        break;

    case NETDEV_DOWN:
        sk->sk_err = ENETDOWN;
        if (!sock_flag(sk, SOCK_DEAD))
            sk->sk_error_report(sk);
        break;
    }

    return NOTIFY_DONE;
}

static int raw_init(struct sock *sk)
{
    struct raw_sock *ro = raw_sk(sk);

    ro->bound            = 0;
    ro->ifindex          = 0;

    /* set default filter to single entry dfilter */
    ro->dfilter.can_id   = 0;
    ro->dfilter.can_mask = MASK_ALL;
    ro->filter           = &ro->dfilter;
    ro->count            = 1;

    /* set default loopback behaviour */
    ro->loopback         = 1;
    ro->recv_own_msgs    = 0;
    ro->fd_frames        = 0;

    /* set notifier */
    ro->notifier.notifier_call = raw_notifier;

    register_netdevice_notifier(&ro->notifier);

    return 0;
}

static int raw_release(struct socket *sock)
{
    struct sock *sk = sock->sk;
    struct raw_sock *ro;

    if (!sk)
        return 0;

    ro = raw_sk(sk);

    unregister_netdevice_notifier(&ro->notifier);

    lock_sock(sk);

    /* remove current filters & unregister */
    if (ro->bound) {
        if (ro->ifindex) {
            struct net_device *dev;

            dev = dev_get_by_index(&init_net, ro->ifindex);
            if (dev) {
                raw_disable_allfilters(dev, sk);
                dev_put(dev);
            }
        } else
            raw_disable_allfilters(NULL, sk);
    }

    if (ro->count > 1)
        kfree(ro->filter);

    ro->ifindex = 0;
    ro->bound   = 0;
    ro->count   = 0;

    sock_orphan(sk);
    sock->sk = NULL;

    release_sock(sk);
    sock_put(sk);

    return 0;
}

static int raw_bind(struct socket *sock, struct sockaddr *uaddr, int len)
{
    struct sockaddr_can *addr = (struct sockaddr_can *)uaddr;
    struct sock *sk = sock->sk;
    struct raw_sock *ro = raw_sk(sk);
    int ifindex;
    int err = 0;
    int notify_enetdown = 0;

    if (len < sizeof(*addr))
        return -EINVAL;

    lock_sock(sk);

    if (ro->bound && addr->can_ifindex == ro->ifindex)
        goto out;

    if (addr->can_ifindex) {
        struct net_device *dev;

        dev = dev_get_by_index(&init_net, addr->can_ifindex);
        if (!dev) {
            err = -ENODEV;
            goto out;
        }
        if (dev->type != ARPHRD_CAN) {
            dev_put(dev);
            err = -ENODEV;
            goto out;
        }
        if (!(dev->flags & IFF_UP))
            notify_enetdown = 1;

        ifindex = dev->ifindex;

        /* filters set by default/setsockopt */
        err = raw_enable_allfilters(dev, sk);
        dev_put(dev);
    } else {
        ifindex = 0;

        /* filters set by default/setsockopt */
        err = raw_enable_allfilters(NULL, sk);
    }

    if (!err) {
        if (ro->bound) {
            /* unregister old filters */
            if (ro->ifindex) {
                struct net_device *dev;

                dev = dev_get_by_index(&init_net, ro->ifindex);
                if (dev) {
                    raw_disable_allfilters(dev, sk);
                    dev_put(dev);
                }
            } else
                raw_disable_allfilters(NULL, sk);
        }
        ro->ifindex = ifindex;
        ro->bound = 1;
    }

 out:
    release_sock(sk);

    if (notify_enetdown) {
        sk->sk_err = ENETDOWN;
        if (!sock_flag(sk, SOCK_DEAD))
            sk->sk_error_report(sk);
    }

    return err;
}

static int raw_getname(struct socket *sock, struct sockaddr *uaddr,
               int *len, int peer)
{
    struct sockaddr_can *addr = (struct sockaddr_can *)uaddr;
    struct sock *sk = sock->sk;
    struct raw_sock *ro = raw_sk(sk);

    if (peer)
        return -EOPNOTSUPP;

    memset(addr, 0, sizeof(*addr));
    addr->can_family  = AF_CAN;
    addr->can_ifindex = ro->ifindex;

    *len = sizeof(*addr);

    return 0;
}

static int raw_setsockopt(struct socket *sock, int level, int optname,
              char __user *optval, unsigned int optlen)
{
    struct sock *sk = sock->sk;
    struct raw_sock *ro = raw_sk(sk);
    struct can_filter *filter = NULL;  /* dyn. alloc'ed filters */
    struct can_filter sfilter;         /* single filter */
    struct net_device *dev = NULL;
    can_err_mask_t err_mask = 0;
    int count = 0;
    int err = 0;

    if (level != SOL_CAN_RAW)
        return -EINVAL;

    switch (optname) {

    case CAN_RAW_FILTER:
        if (optlen % sizeof(struct can_filter) != 0)
            return -EINVAL;

        count = optlen / sizeof(struct can_filter);

        if (count > 1) {
            /* filter does not fit into dfilter => alloc space */
            filter = memdup_user(optval, optlen);
            if (IS_ERR(filter))
                return PTR_ERR(filter);
        } else if (count == 1) {
            if (copy_from_user(&sfilter, optval, sizeof(sfilter)))
                return -EFAULT;
        }

        lock_sock(sk);

        if (ro->bound && ro->ifindex)
            dev = dev_get_by_index(&init_net, ro->ifindex);

        if (ro->bound) {
            /* (try to) register the new filters */
            if (count == 1)
                err = raw_enable_filters(dev, sk, &sfilter, 1);
            else
                err = raw_enable_filters(dev, sk, filter,
                             count);
            if (err) {
                if (count > 1)
                    kfree(filter);
                goto out_fil;
            }

            /* remove old filter registrations */
            raw_disable_filters(dev, sk, ro->filter, ro->count);
        }

        /* remove old filter space */
        if (ro->count > 1)
            kfree(ro->filter);

        /* link new filters to the socket */
        if (count == 1) {
            /* copy filter data for single filter */
            ro->dfilter = sfilter;
            filter = &ro->dfilter;
        }
        ro->filter = filter;
        ro->count  = count;

 out_fil:
        if (dev)
            dev_put(dev);

        release_sock(sk);

        break;

    case CAN_RAW_ERR_FILTER:
        if (optlen != sizeof(err_mask))
            return -EINVAL;

        if (copy_from_user(&err_mask, optval, optlen))
            return -EFAULT;

        err_mask &= CAN_ERR_MASK;

        lock_sock(sk);

        if (ro->bound && ro->ifindex)
            dev = dev_get_by_index(&init_net, ro->ifindex);

        /* remove current error mask */
        if (ro->bound) {
            /* (try to) register the new err_mask */
            err = raw_enable_errfilter(dev, sk, err_mask);

            if (err)
                goto out_err;

            /* remove old err_mask registration */
            raw_disable_errfilter(dev, sk, ro->err_mask);
        }

        /* link new err_mask to the socket */
        ro->err_mask = err_mask;

 out_err:
        if (dev)
            dev_put(dev);

        release_sock(sk);

        break;

    case CAN_RAW_LOOPBACK:
        if (optlen != sizeof(ro->loopback))
            return -EINVAL;

        if (copy_from_user(&ro->loopback, optval, optlen))
            return -EFAULT;

        break;

    case CAN_RAW_RECV_OWN_MSGS:
        if (optlen != sizeof(ro->recv_own_msgs))
            return -EINVAL;

        if (copy_from_user(&ro->recv_own_msgs, optval, optlen))
            return -EFAULT;

        break;

    case CAN_RAW_FD_FRAMES:
        if (optlen != sizeof(ro->fd_frames))
            return -EINVAL;

        if (copy_from_user(&ro->fd_frames, optval, optlen))
            return -EFAULT;

        break;

    default:
        return -ENOPROTOOPT;
    }
    return err;
}

static int raw_getsockopt(struct socket *sock, int level, int optname,
              char __user *optval, int __user *optlen)
{
    struct sock *sk = sock->sk;
    struct raw_sock *ro = raw_sk(sk);
    int len;
    void *val;
    int err = 0;

    if (level != SOL_CAN_RAW)
        return -EINVAL;
    if (get_user(len, optlen))
        return -EFAULT;
    if (len < 0)
        return -EINVAL;

    switch (optname) {

    case CAN_RAW_FILTER:
        lock_sock(sk);
        if (ro->count > 0) {
            int fsize = ro->count * sizeof(struct can_filter);
            if (len > fsize)
                len = fsize;
            if (copy_to_user(optval, ro->filter, len))
                err = -EFAULT;
        } else
            len = 0;
        release_sock(sk);

        if (!err)
            err = put_user(len, optlen);
        return err;

    case CAN_RAW_ERR_FILTER:
        if (len > sizeof(can_err_mask_t))
            len = sizeof(can_err_mask_t);
        val = &ro->err_mask;
        break;

    case CAN_RAW_LOOPBACK:
        if (len > sizeof(int))
            len = sizeof(int);
        val = &ro->loopback;
        break;

    case CAN_RAW_RECV_OWN_MSGS:
        if (len > sizeof(int))
            len = sizeof(int);
        val = &ro->recv_own_msgs;
        break;

    case CAN_RAW_FD_FRAMES:
        if (len > sizeof(int))
            len = sizeof(int);
        val = &ro->fd_frames;
        break;

    default:
        return -ENOPROTOOPT;
    }

    if (put_user(len, optlen))
        return -EFAULT;
    if (copy_to_user(optval, val, len))
        return -EFAULT;
    return 0;
}

static int raw_sendmsg(struct kiocb *iocb, struct socket *sock,
               struct msghdr *msg, size_t size)
{
    struct sock *sk = sock->sk;
    struct raw_sock *ro = raw_sk(sk);
    struct sk_buff *skb;
    struct net_device *dev;
    int ifindex;
    int err;

    if (msg->msg_name) {
        struct sockaddr_can *addr =
            (struct sockaddr_can *)msg->msg_name;

        if (msg->msg_namelen < sizeof(*addr))
            return -EINVAL;

        if (addr->can_family != AF_CAN)
            return -EINVAL;

        ifindex = addr->can_ifindex;
    } else
        ifindex = ro->ifindex;

    if (ro->fd_frames) {
        if (unlikely(size != CANFD_MTU && size != CAN_MTU))
            return -EINVAL;
    } else {
        if (unlikely(size != CAN_MTU))
            return -EINVAL;
    }

    dev = dev_get_by_index(&init_net, ifindex);
    if (!dev)
        return -ENXIO;

    skb = sock_alloc_send_skb(sk, size, msg->msg_flags & MSG_DONTWAIT,
                  &err);
    if (!skb)
        goto put_dev;

    err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
    if (err < 0)
        goto free_skb;
    err = sock_tx_timestamp(sk, &skb_shinfo(skb)->tx_flags);
    if (err < 0)
        goto free_skb;

    skb->dev = dev;
    skb->sk  = sk;

    err = can_send(skb, ro->loopback);

    dev_put(dev);

    if (err)
        goto send_failed;

    return size;

free_skb:
    kfree_skb(skb);
put_dev:
    dev_put(dev);
send_failed:
    return err;
}

static int raw_recvmsg(struct kiocb *iocb, struct socket *sock,
               struct msghdr *msg, size_t size, int flags)
{
    struct sock *sk = sock->sk;
    struct raw_sock *ro = raw_sk(sk);
    struct sk_buff *skb;
    int rxmtu;
    int err = 0;
    int noblock;

    noblock =  flags & MSG_DONTWAIT;
    flags   &= ~MSG_DONTWAIT;

    skb = skb_recv_datagram(sk, flags, noblock, &err);
    if (!skb)
        return err;

    /*
     * when serving a legacy socket the DLC <= 8 is already checked inside
     * raw_rcv(). Now check if we need to pass a canfd_frame to a legacy
     * socket and cut the possible CANFD_MTU/CAN_MTU length to CAN_MTU
     */
    if (!ro->fd_frames)
        rxmtu = CAN_MTU;
    else
        rxmtu = skb->len;

    if (size < rxmtu)
        msg->msg_flags |= MSG_TRUNC;
    else
        size = rxmtu;

    err = memcpy_toiovec(msg->msg_iov, skb->data, size);
    if (err < 0) {
        skb_free_datagram(sk, skb);
        return err;
    }

    sock_recv_ts_and_drops(msg, sk, skb);

    if (msg->msg_name) {
        msg->msg_namelen = sizeof(struct sockaddr_can);
        memcpy(msg->msg_name, skb->cb, msg->msg_namelen);
    }

    /* assign the flags that have been recorded in raw_rcv() */
    msg->msg_flags |= *(raw_flags(skb));

    skb_free_datagram(sk, skb);

    return size;
}

static const struct proto_ops raw_ops = {
    .family        = PF_CAN,
    .release       = raw_release,
    .bind          = raw_bind,
    .connect       = sock_no_connect,
    .socketpair    = sock_no_socketpair,
    .accept        = sock_no_accept,
    .getname       = raw_getname,
    .poll          = datagram_poll,
    .ioctl         = can_ioctl, /* use can_ioctl() from af_can.c */
    .listen        = sock_no_listen,
    .shutdown      = sock_no_shutdown,
    .setsockopt    = raw_setsockopt,
    .getsockopt    = raw_getsockopt,
    .sendmsg       = raw_sendmsg,
    .recvmsg       = raw_recvmsg,
    .mmap          = sock_no_mmap,
    .sendpage      = sock_no_sendpage,
};

static struct proto raw_proto __read_mostly = {
    .name       = "CAN_RAW",
    .owner      = THIS_MODULE,
    .obj_size   = sizeof(struct raw_sock),
    .init       = raw_init,
};

static const struct can_proto raw_can_proto = {
    .type       = SOCK_RAW,
    .protocol   = CAN_RAW,
    .ops        = &raw_ops,
    .prot       = &raw_proto,
};

static __init int raw_module_init(void)
{
    int err;

    printk(banner);

    err = can_proto_register(&raw_can_proto);
    if (err < 0)
        printk(KERN_ERR "can: registration of raw protocol failed\n");

    return err;
}

static __exit void raw_module_exit(void)
{
    can_proto_unregister(&raw_can_proto);
}

module_init(raw_module_init);
module_exit(raw_module_exit);