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Message-ID: <20071114133837.6b899595@freepuppy.rosehill>
Date: Wed, 14 Nov 2007 13:38:37 -0800
From: Stephen Hemminger <shemminger@...ux-foundation.org>
To: Urs Thuermann <urs.thuermann@....de>
Cc: netdev@...r.kernel.org, David Miller <davem@...emloft.net>,
Patrick McHardy <kaber@...sh.net>,
Urs Thuermann <urs.thuermann@...kswagen.de>,
Oliver Hartkopp <oliver.hartkopp@...kswagen.de>
Subject: Re: [PATCH 2/7] CAN: Add PF_CAN core module
On Wed, 14 Nov 2007 13:13:41 +0100
Urs Thuermann <urs.thuermann@....de> wrote:
> This patch adds the CAN core functionality but no protocols or drivers.
> No protocol implementations are included here. They come as separate
> patches. Protocol numbers are already in include/linux/can.h.
>
> Signed-off-by: Oliver Hartkopp <oliver.hartkopp@...kswagen.de>
> Signed-off-by: Urs Thuermann <urs.thuermann@...kswagen.de>
>
> ---
> include/linux/can.h | 111 +++++
> include/linux/can/core.h | 78 +++
> include/linux/can/error.h | 93 ++++
> net/Kconfig | 1
> net/Makefile | 1
> net/can/Kconfig | 25 +
> net/can/Makefile | 6
> net/can/af_can.c | 975 ++++++++++++++++++++++++++++++++++++++++++++++
> net/can/af_can.h | 120 +++++
> net/can/proc.c | 532 +++++++++++++++++++++++++
> 10 files changed, 1942 insertions(+)
> Index: net-2.6.25/include/linux/can/core.h
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ net-2.6.25/include/linux/can/core.h 2007-11-14 13:04:49.000000000 +0100
> @@ -0,0 +1,78 @@
> +/*
> + * linux/can/core.h
> + *
> + * Protoypes and definitions for CAN protocol modules using the PF_CAN core
> + *
> + * Authors: Oliver Hartkopp <oliver.hartkopp@...kswagen.de>
> + * Urs Thuermann <urs.thuermann@...kswagen.de>
> + * Copyright (c) 2002-2007 Volkswagen Group Electronic Research
> + * All rights reserved.
> + *
> + * Send feedback to <socketcan-users@...ts.berlios.de>
> + *
> + */
> +
> +#ifndef CAN_CORE_H
> +#define CAN_CORE_H
> +
> +#include <linux/can.h>
> +#include <linux/skbuff.h>
> +#include <linux/netdevice.h>
> +
> +#define CAN_VERSION "20071027"
> +
> +/* increment this number each time you change some user-space interface */
> +#define CAN_ABI_VERSION "8"
> +
> +#define CAN_VERSION_STRING "rev " CAN_VERSION " abi " CAN_ABI_VERSION
> +
> +#define DNAME(dev) ((dev) ? (dev)->name : "any")
> +
> +/**
> + * struct can_proto - CAN protocol structure
> + * @type: type argument in socket() syscall, e.g. SOCK_DGRAM.
> + * @protocol: protocol number in socket() syscall.
> + * @capability: capability needed to open the socket, or -1 for no restriction.
> + * @ops: pointer to struct proto_ops for sock->ops.
> + * @prot: pointer to struct proto structure.
> + */
> +struct can_proto {
> + int type;
> + int protocol;
> + int capability;
> + struct proto_ops *ops;
> + struct proto *prot;
> +};
> +
> +/* function prototypes for the CAN networklayer core (af_can.c) */
> +
> +extern int can_proto_register(struct can_proto *cp);
> +extern void can_proto_unregister(struct can_proto *cp);
> +
> +extern int can_rx_register(struct net_device *dev, canid_t can_id,
> + canid_t mask,
> + void (*func)(struct sk_buff *, void *),
> + void *data, char *ident);
> +
> +extern void can_rx_unregister(struct net_device *dev, canid_t can_id,
> + canid_t mask,
> + void (*func)(struct sk_buff *, void *),
> + void *data);
> +
> +extern int can_send(struct sk_buff *skb, int loop);
> +
> +#ifdef CONFIG_CAN_DEBUG_CORE
> +extern void can_debug_skb(struct sk_buff *skb);
> +extern void can_debug_cframe(const char *msg, struct can_frame *cframe);
> +#define DBG(fmt, args...) (DBG_VAR & 1 ? printk( \
> + KERN_DEBUG DBG_PREFIX ": %s: " fmt, \
> + __func__, ##args) : 0)
> +#define DBG_FRAME(fmt, cf) (DBG_VAR & 2 ? can_debug_cframe(fmt, cf) : 0)
> +#define DBG_SKB(skb) (DBG_VAR & 4 ? can_debug_skb(skb) : 0)
> +#else
> +#define DBG(fmt, args...)
> +#define DBG_FRAME(fmt, cf)
> +#define DBG_SKB(skb)
> +#endif
This non-standard debugging seems like it needs a better interface.
Also, need paren's around (DBG_VAR & 1) and don't use UPPERCASE for
variable names.
> +
> +#endif /* CAN_CORE_H */
> Index: net-2.6.25/net/Kconfig
> ===================================================================
> --- net-2.6.25.orig/net/Kconfig 2007-11-14 13:04:26.000000000 +0100
> +++ net-2.6.25/net/Kconfig 2007-11-14 13:04:49.000000000 +0100
> @@ -218,6 +218,7 @@
> endmenu
>
> source "net/ax25/Kconfig"
> +source "net/can/Kconfig"
> source "net/irda/Kconfig"
> source "net/bluetooth/Kconfig"
> source "net/rxrpc/Kconfig"
> Index: net-2.6.25/net/Makefile
> ===================================================================
> --- net-2.6.25.orig/net/Makefile 2007-11-14 13:04:26.000000000 +0100
> +++ net-2.6.25/net/Makefile 2007-11-14 13:04:49.000000000 +0100
> @@ -34,6 +34,7 @@
> obj-$(CONFIG_NETROM) += netrom/
> obj-$(CONFIG_ROSE) += rose/
> obj-$(CONFIG_AX25) += ax25/
> +obj-$(CONFIG_CAN) += can/
> obj-$(CONFIG_IRDA) += irda/
> obj-$(CONFIG_BT) += bluetooth/
> obj-$(CONFIG_SUNRPC) += sunrpc/
> Index: net-2.6.25/net/can/Kconfig
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ net-2.6.25/net/can/Kconfig 2007-11-14 13:04:49.000000000 +0100
> @@ -0,0 +1,25 @@
> +#
> +# Controller Area Network (CAN) network layer core configuration
> +#
> +
> +menuconfig CAN
> + depends on NET
> + tristate "CAN bus subsystem support"
> + ---help---
> + Controller Area Network (CAN) is a slow (up to 1Mbit/s) serial
> + communications protocol which was developed by Bosch in
> + 1991, mainly for automotive, but now widely used in marine
> + (NMEA2000), industrial, and medical applications.
> + More information on the CAN network protocol family PF_CAN
> + is contained in <Documentation/networking/can.txt>.
> +
> + If you want CAN support you should say Y here and also to the
> + specific driver for your controller(s) below.
> +
> +config CAN_DEBUG_CORE
> + bool "CAN Core debugging messages"
> + depends on CAN
> + ---help---
> + Say Y here if you want the CAN core to produce a bunch of debug
> + messages. Select this if you are having a problem with CAN
> + support and want to see more of what is going on.
> Index: net-2.6.25/net/can/Makefile
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ net-2.6.25/net/can/Makefile 2007-11-14 13:04:49.000000000 +0100
> @@ -0,0 +1,6 @@
> +#
> +# Makefile for the Linux Controller Area Network core.
> +#
> +
> +obj-$(CONFIG_CAN) += can.o
> +can-objs := af_can.o proc.o
> Index: net-2.6.25/net/can/af_can.c
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ net-2.6.25/net/can/af_can.c 2007-11-14 13:04:49.000000000 +0100
> @@ -0,0 +1,975 @@
> +/*
> + * af_can.c - Protocol family CAN core module
> + * (used by different CAN protocol modules)
> + *
> + * 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.
> + *
> + * Send feedback to <socketcan-users@...ts.berlios.de>
> + *
> + */
> +
> +#include <linux/module.h>
> +#include <linux/init.h>
> +#include <linux/kmod.h>
> +#include <linux/slab.h>
> +#include <linux/list.h>
> +#include <linux/spinlock.h>
> +#include <linux/rcupdate.h>
> +#include <linux/uaccess.h>
> +#include <linux/net.h>
> +#include <linux/netdevice.h>
> +#include <linux/socket.h>
> +#include <linux/if_ether.h>
> +#include <linux/if_arp.h>
> +#include <linux/skbuff.h>
> +#include <linux/can.h>
> +#include <linux/can/core.h>
> +#include <net/net_namespace.h>
> +#include <net/sock.h>
> +
> +#include "af_can.h"
> +
> +static __initdata const char banner[] = KERN_INFO
> + "can: controller area network core (" CAN_VERSION_STRING ")\n";
> +
> +MODULE_DESCRIPTION("Controller Area Network PF_CAN core");
> +MODULE_LICENSE("Dual BSD/GPL");
> +MODULE_AUTHOR("Urs Thuermann <urs.thuermann@...kswagen.de>, "
> + "Oliver Hartkopp <oliver.hartkopp@...kswagen.de>");
> +
> +MODULE_ALIAS_NETPROTO(PF_CAN);
> +
> +static int stats_timer __read_mostly = 1;
> +module_param(stats_timer, int, S_IRUGO);
> +MODULE_PARM_DESC(stats_timer, "enable timer for statistics (default:on)");
> +
> +#ifdef CONFIG_CAN_DEBUG_CORE
> +#define DBG_PREFIX "can"
> +#define DBG_VAR can_debug
> +static int can_debug __read_mostly;
> +module_param_named(debug, can_debug, int, S_IRUGO);
> +MODULE_PARM_DESC(debug, "debug print mask: 1:debug, 2:frames, 4:skbs");
> +#endif
> +
> +HLIST_HEAD(rx_dev_list);
Please either make rx_dev_list static or call it can_rx_dev_list
to avoid name conflices.
> +static struct dev_rcv_lists rx_alldev_list;
> +static DEFINE_SPINLOCK(rcv_lists_lock);
> +
> +static struct kmem_cache *rcv_cache __read_mostly;
> +
> +/* table of registered CAN protocols */
> +static struct can_proto *proto_tab[CAN_NPROTO] __read_mostly;
> +static DEFINE_SPINLOCK(proto_tab_lock);
> +
> +struct timer_list stattimer; /* timer for statistics update */
> +struct s_stats stats; /* packet statistics */
> +struct s_pstats pstats; /* receive list statistics */
More global variables without prefix.
> +/*
> + * af_can socket functions
> + */
> +
> +static int can_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
> +{
> + struct sock *sk = sock->sk;
> +
> + switch (cmd) {
> +
> + case SIOCGSTAMP:
> + return sock_get_timestamp(sk, (struct timeval __user *)arg);
> +
> + default:
> + return -ENOIOCTLCMD;
> + }
> +}
> +
> +static void can_sock_destruct(struct sock *sk)
> +{
> + DBG("called for sock %p\n", sk);
> +
> + skb_queue_purge(&sk->sk_receive_queue);
> +}
> +
> +static int can_create(struct net *net, struct socket *sock, int protocol)
> +{
> + struct sock *sk;
> + struct can_proto *cp;
> + char module_name[sizeof("can-proto-000")];
> + int err = 0;
> +
> + DBG("socket %p, type %d, proto %d\n", sock, sock->type, protocol);
> +
> + sock->state = SS_UNCONNECTED;
> +
> + if (protocol < 0 || protocol >= CAN_NPROTO)
> + return -EINVAL;
> +
> + if (net != &init_net)
> + return -EAFNOSUPPORT;
> +
> + DBG("looking up proto %d in proto_tab[]\n", protocol);
> +
> + /* try to load protocol module, when CONFIG_KMOD is defined */
> + if (!proto_tab[protocol]) {
> + sprintf(module_name, "can-proto-%d", protocol);
> + err = request_module(module_name);
> +
> + /*
> + * In case of error we only print a message but don't
> + * return the error code immediately. Below we will
> + * return -EPROTONOSUPPORT
> + */
> + if (err == -ENOSYS) {
> + if (printk_ratelimit())
> + printk(KERN_INFO "can: request_module(%s)"
> + " not implemented.\n", module_name);
> + } else if (err) {
> + if (printk_ratelimit())
> + printk(KERN_ERR "can: request_module(%s)"
> + " failed.\n", module_name);
> + }
> + }
> +
> + spin_lock(&proto_tab_lock);
> + cp = proto_tab[protocol];
> + if (cp && !try_module_get(cp->prot->owner))
> + cp = NULL;
> + spin_unlock(&proto_tab_lock);
> +
> + /* check for available protocol and correct usage */
> +
> + if (!cp)
> + return -EPROTONOSUPPORT;
> +
> + if (cp->type != sock->type) {
> + err = -EPROTONOSUPPORT;
> + goto errout;
> + }
> +
> + if (cp->capability >= 0 && !capable(cp->capability)) {
> + err = -EPERM;
> + goto errout;
> + }
> +
> + sock->ops = cp->ops;
> +
> + sk = sk_alloc(net, PF_CAN, GFP_KERNEL, cp->prot);
> + if (!sk) {
> + err = -ENOMEM;
> + goto errout;
> + }
> +
> + sock_init_data(sock, sk);
> + sk->sk_destruct = can_sock_destruct;
> +
> + DBG("created sock: %p\n", sk);
> +
> + if (sk->sk_prot->init)
> + err = sk->sk_prot->init(sk);
> +
> + if (err) {
> + /* release sk on errors */
> + sock_orphan(sk);
> + sock_put(sk);
> + }
> +
> + errout:
> + module_put(cp->prot->owner);
> + return err;
> +}
> +
> +/*
> + * af_can tx path
> + */
> +
> +/**
> + * can_send - transmit a CAN frame (optional with local loopback)
> + * @skb: pointer to socket buffer with CAN frame in data section
> + * @loop: loopback for listeners on local CAN sockets (recommended default!)
> + *
> + * Return:
> + * 0 on success
> + * -ENETDOWN when the selected interface is down
> + * -ENOBUFS on full driver queue (see net_xmit_errno())
> + * -ENOMEM when local loopback failed at calling skb_clone()
> + * -EPERM when trying to send on a non-CAN interface
> + */
> +int can_send(struct sk_buff *skb, int loop)
> +{
> + int err;
> +
> + if (skb->dev->type != ARPHRD_CAN) {
> + kfree_skb(skb);
> + return -EPERM;
> + }
> +
> + if (!(skb->dev->flags & IFF_UP)) {
> + kfree_skb(skb);
> + return -ENETDOWN;
> + }
> +
> + skb->protocol = htons(ETH_P_CAN);
> + skb_reset_network_header(skb);
> + skb_reset_transport_header(skb);
> +
> + if (loop) {
> + /* local loopback of sent CAN frames */
> +
> + /* indication for the CAN driver: do loopback */
> + skb->pkt_type = PACKET_LOOPBACK;
> +
> + /*
> + * The reference to the originating sock may be required
> + * by the receiving socket to check whether the frame is
> + * its own. Example: can_raw sockopt CAN_RAW_RECV_OWN_MSGS
> + * Therefore we have to ensure that skb->sk remains the
> + * reference to the originating sock by restoring skb->sk
> + * after each skb_clone() or skb_orphan() usage.
> + */
> +
> + if (!(skb->dev->flags & IFF_ECHO)) {
> + /*
> + * If the interface is not capable to do loopback
> + * itself, we do it here.
> + */
> + struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
> +
> + if (!newskb) {
> + kfree_skb(skb);
> + return -ENOMEM;
> + }
> +
> + newskb->sk = skb->sk;
> + newskb->ip_summed = CHECKSUM_UNNECESSARY;
> + newskb->pkt_type = PACKET_BROADCAST;
> + netif_rx(newskb);
> + }
> + } else {
> + /* indication for the CAN driver: no loopback required */
> + skb->pkt_type = PACKET_HOST;
> + }
> +
> + /* send to netdevice */
> + err = dev_queue_xmit(skb);
> + if (err > 0)
> + err = net_xmit_errno(err);
> +
> + /* update statistics */
> + stats.tx_frames++;
> + stats.tx_frames_delta++;
> +
> + return err;
> +}
> +EXPORT_SYMBOL(can_send);
> +
> +/*
> + * af_can rx path
> + */
> +
> +static struct dev_rcv_lists *find_dev_rcv_lists(struct net_device *dev)
> +{
> + struct dev_rcv_lists *d = NULL;
> + struct hlist_node *n;
> +
> + /*
> + * find receive list for this device
> + *
> + * The hlist_for_each_entry*() macros curse through the list
> + * using the pointer variable n and set d to the containing
> + * struct in each list iteration. Therefore, after list
> + * iteration, d is unmodified when the list is empty, and it
> + * points to last list element, when the list is non-empty
> + * but no match in the loop body is found. I.e. d is *not*
> + * NULL when no match is found. We can, however, use the
> + * cursor variable n to decide if a match was found.
> + */
> +
> + hlist_for_each_entry_rcu(d, n, &rx_dev_list, list) {
> + if (d->dev == dev)
> + break;
> + }
> +
> + return n ? d : NULL;
> +}
> +
> +static struct hlist_head *find_rcv_list(canid_t *can_id, canid_t *mask,
> + struct dev_rcv_lists *d)
> +{
> + canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */
> +
> + /* filter error frames */
> + if (*mask & CAN_ERR_FLAG) {
> + /* clear CAN_ERR_FLAG in list entry */
> + *mask &= CAN_ERR_MASK;
> + return &d->rx[RX_ERR];
> + }
> +
> + /* ensure valid values in can_mask */
> + if (*mask & CAN_EFF_FLAG)
> + *mask &= (CAN_EFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG);
> + else
> + *mask &= (CAN_SFF_MASK | CAN_RTR_FLAG);
> +
> + /* reduce condition testing at receive time */
> + *can_id &= *mask;
> +
> + /* inverse can_id/can_mask filter */
> + if (inv)
> + return &d->rx[RX_INV];
> +
> + /* mask == 0 => no condition testing at receive time */
> + if (!(*mask))
> + return &d->rx[RX_ALL];
> +
> + /* use extra filterset for the subscription of exactly *ONE* can_id */
> + if (*can_id & CAN_EFF_FLAG) {
> + if (*mask == (CAN_EFF_MASK | CAN_EFF_FLAG)) {
> + /* RFC: a use-case for hash-tables in the future? */
> + return &d->rx[RX_EFF];
> + }
> + } else {
> + if (*mask == CAN_SFF_MASK)
> + return &d->rx_sff[*can_id];
> + }
> +
> + /* default: filter via can_id/can_mask */
> + return &d->rx[RX_FIL];
> +}
> +
> +/**
> + * can_rx_register - subscribe CAN frames from a specific interface
> + * @dev: pointer to netdevice (NULL => subcribe from 'all' CAN devices list)
> + * @can_id: CAN identifier (see description)
> + * @mask: CAN mask (see description)
> + * @func: callback function on filter match
> + * @data: returned parameter for callback function
> + * @ident: string for calling module indentification
> + *
> + * Description:
> + * Invokes the callback function with the received sk_buff and the given
> + * parameter 'data' on a matching receive filter. A filter matches, when
> + *
> + * <received_can_id> & mask == can_id & mask
> + *
> + * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
> + * filter for error frames (CAN_ERR_FLAG bit set in mask).
> + *
> + * Return:
> + * 0 on success
> + * -ENOMEM on missing cache mem to create subscription entry
> + * -ENODEV unknown device
> + */
> +int can_rx_register(struct net_device *dev, canid_t can_id, canid_t mask,
> + void (*func)(struct sk_buff *, void *), void *data,
> + char *ident)
> +{
> + struct receiver *r;
> + struct hlist_head *rl;
> + struct dev_rcv_lists *d;
> + int err = 0;
> +
> + /* insert new receiver (dev,canid,mask) -> (func,data) */
> +
> + DBG("dev %p (%s), id %03X, mask %03X, callback %p, data %p, "
> + "ident %s\n", dev, DNAME(dev), can_id, mask, func, data, ident);
> +
> + r = kmem_cache_alloc(rcv_cache, GFP_KERNEL);
> + if (!r)
> + return -ENOMEM;
> +
> + spin_lock(&rcv_lists_lock);
> +
> + d = find_dev_rcv_lists(dev);
> + if (d) {
> + rl = find_rcv_list(&can_id, &mask, d);
> +
> + r->can_id = can_id;
> + r->mask = mask;
> + r->matches = 0;
> + r->func = func;
> + r->data = data;
> + r->ident = ident;
> +
> + hlist_add_head_rcu(&r->list, rl);
> + d->entries++;
> +
> + pstats.rcv_entries++;
> + if (pstats.rcv_entries_max < pstats.rcv_entries)
> + pstats.rcv_entries_max = pstats.rcv_entries;
> + } else {
> + DBG("receive list not found for dev %s, id %03X, mask %03X\n",
> + DNAME(dev), can_id, mask);
> + kmem_cache_free(rcv_cache, r);
> + err = -ENODEV;
> + }
> +
> + spin_unlock(&rcv_lists_lock);
> +
> + return err;
> +}
> +EXPORT_SYMBOL(can_rx_register);
> +
> +/*
> + * can_rx_delete_device - rcu callback for dev_rcv_lists structure removal
> + */
> +static void can_rx_delete_device(struct rcu_head *rp)
> +{
> + struct dev_rcv_lists *d = container_of(rp, struct dev_rcv_lists, rcu);
> +
> + DBG("removing dev_rcv_list at %p\n", d);
> + kfree(d);
> +}
> +
> +/*
> + * can_rx_delete_receiver - rcu callback for single receiver entry removal
> + */
> +static void can_rx_delete_receiver(struct rcu_head *rp)
> +{
> + struct receiver *r = container_of(rp, struct receiver, rcu);
> +
> + DBG("removing receiver at %p\n", r);
> + kmem_cache_free(rcv_cache, r);
> +}
> +
> +/**
> + * can_rx_unregister - unsubscribe CAN frames from a specific interface
> + * @dev: pointer to netdevice (NULL => unsubcribe from 'all' CAN devices list)
> + * @can_id: CAN identifier
> + * @mask: CAN mask
> + * @func: callback function on filter match
> + * @data: returned parameter for callback function
> + *
> + * Description:
> + * Removes subscription entry depending on given (subscription) values.
> + */
> +void can_rx_unregister(struct net_device *dev, canid_t can_id, canid_t mask,
> + void (*func)(struct sk_buff *, void *), void *data)
> +{
> + struct receiver *r = NULL;
> + struct hlist_head *rl;
> + struct hlist_node *next;
> + struct dev_rcv_lists *d;
> +
> + DBG("dev %p (%s), id %03X, mask %03X, callback %p, data %p\n",
> + dev, DNAME(dev), can_id, mask, func, data);
> +
> + spin_lock(&rcv_lists_lock);
> +
> + d = find_dev_rcv_lists(dev);
> + if (!d) {
> + printk(KERN_ERR "BUG: receive list not found for "
> + "dev %s, id %03X, mask %03X\n",
> + DNAME(dev), can_id, mask);
> + goto out;
> + }
> +
> + rl = find_rcv_list(&can_id, &mask, d);
> +
> + /*
> + * Search the receiver list for the item to delete. This should
> + * exist, since no receiver may be unregistered that hasn't
> + * been registered before.
> + */
> +
> + hlist_for_each_entry_rcu(r, next, rl, list) {
> + if (r->can_id == can_id && r->mask == mask
> + && r->func == func && r->data == data)
> + break;
> + }
> +
> + /*
> + * Check for bugs in CAN protocol implementations:
> + * If no matching list item was found, the list cursor variable next
> + * will be NULL, while r will point to the last item of the list.
> + */
> +
> + if (!next) {
> + printk(KERN_ERR "BUG: receive list entry not found for "
> + "dev %s, id %03X, mask %03X\n",
> + DNAME(dev), can_id, mask);
> + r = NULL;
> + d = NULL;
> + goto out;
> + }
> +
> + hlist_del_rcu(&r->list);
> + d->entries--;
> +
> + if (pstats.rcv_entries > 0)
> + pstats.rcv_entries--;
> +
> + /* remove device structure requested by NETDEV_UNREGISTER */
> + if (d->remove_on_zero_entries && !d->entries) {
> + DBG("removing dev_rcv_list for %s on zero entries\n",
> + dev->name);
> + hlist_del_rcu(&d->list);
> + } else
> + d = NULL;
> +
> + out:
> + spin_unlock(&rcv_lists_lock);
> +
> + /* schedule the receiver item for deletion */
> + if (r)
> + call_rcu(&r->rcu, can_rx_delete_receiver);
> +
> + /* schedule the device structure for deletion */
> + if (d)
> + call_rcu(&d->rcu, can_rx_delete_device);
> +}
> +EXPORT_SYMBOL(can_rx_unregister);
> +
> +static inline void deliver(struct sk_buff *skb, struct receiver *r)
> +{
> + struct sk_buff *clone = skb_clone(skb, GFP_ATOMIC);
> +
> + DBG("skbuff %p cloned to %p\n", skb, clone);
> + if (clone) {
> + clone->sk = skb->sk;
> + r->func(clone, r->data);
> + r->matches++;
> + }
> +}
> +
> +static int can_rcv_filter(struct dev_rcv_lists *d, struct sk_buff *skb)
> +{
> + struct receiver *r;
> + struct hlist_node *n;
> + int matches = 0;
> + struct can_frame *cf = (struct can_frame *)skb->data;
> + canid_t can_id = cf->can_id;
> +
> + if (d->entries == 0)
> + return 0;
> +
> + if (can_id & CAN_ERR_FLAG) {
> + /* check for error frame entries only */
> + hlist_for_each_entry_rcu(r, n, &d->rx[RX_ERR], list) {
> + if (can_id & r->mask) {
> + DBG("match on rx_err skbuff %p\n", skb);
> + deliver(skb, r);
> + matches++;
> + }
> + }
> + return matches;
> + }
> +
> + /* check for unfiltered entries */
> + hlist_for_each_entry_rcu(r, n, &d->rx[RX_ALL], list) {
> + DBG("match on rx_all skbuff %p\n", skb);
> + deliver(skb, r);
> + matches++;
> + }
> +
> + /* check for can_id/mask entries */
> + hlist_for_each_entry_rcu(r, n, &d->rx[RX_FIL], list) {
> + if ((can_id & r->mask) == r->can_id) {
> + DBG("match on rx_fil skbuff %p\n", skb);
> + deliver(skb, r);
> + matches++;
> + }
> + }
> +
> + /* check for inverted can_id/mask entries */
> + hlist_for_each_entry_rcu(r, n, &d->rx[RX_INV], list) {
> + if ((can_id & r->mask) != r->can_id) {
> + DBG("match on rx_inv skbuff %p\n", skb);
> + deliver(skb, r);
> + matches++;
> + }
> + }
> +
> + /* check CAN_ID specific entries */
> + if (can_id & CAN_EFF_FLAG) {
> + hlist_for_each_entry_rcu(r, n, &d->rx[RX_EFF], list) {
> + if (r->can_id == can_id) {
> + DBG("match on rx_eff skbuff %p\n", skb);
> + deliver(skb, r);
> + matches++;
> + }
> + }
> + } else {
> + can_id &= CAN_SFF_MASK;
> + hlist_for_each_entry_rcu(r, n, &d->rx_sff[can_id], list) {
> + DBG("match on rx_sff skbuff %p\n", skb);
> + deliver(skb, r);
> + matches++;
> + }
> + }
> +
> + return matches;
> +}
> +
> +static int can_rcv(struct sk_buff *skb, struct net_device *dev,
> + struct packet_type *pt, struct net_device *orig_dev)
> +{
> + struct dev_rcv_lists *d;
> + int matches;
> +
> + DBG("received skbuff on device %s, ptype %04x\n",
> + dev->name, ntohs(pt->type));
> + DBG_SKB(skb);
> + DBG_FRAME("can: can_rcv: received CAN frame",
> + (struct can_frame *)skb->data);
> +
> + if (dev->type != ARPHRD_CAN || dev->nd_net != &init_net) {
> + kfree_skb(skb);
> + return 0;
> + }
> +
> + /* update statistics */
> + stats.rx_frames++;
> + stats.rx_frames_delta++;
> +
> + rcu_read_lock();
> +
> + /* deliver the packet to sockets listening on all devices */
> + matches = can_rcv_filter(&rx_alldev_list, skb);
> +
> + /* find receive list for this device */
> + d = find_dev_rcv_lists(dev);
> + if (d)
> + matches += can_rcv_filter(d, skb);
> +
> + rcu_read_unlock();
> +
> + /* free the skbuff allocated by the netdevice driver */
> + DBG("freeing skbuff %p\n", skb);
> + kfree_skb(skb);
> +
> + if (matches > 0) {
> + stats.matches++;
> + stats.matches_delta++;
> + }
> +
> + return 0;
> +}
> +
> +/*
> + * af_can protocol functions
> + */
> +
> +/**
> + * can_proto_register - register CAN transport protocol
> + * @cp: pointer to CAN protocol structure
> + *
> + * Return:
> + * 0 on success
> + * -EINVAL invalid (out of range) protocol number
> + * -EBUSY protocol already in use
> + * -ENOBUF if proto_register() fails
> + */
> +int can_proto_register(struct can_proto *cp)
> +{
> + int proto = cp->protocol;
> + int err = 0;
> +
> + if (proto < 0 || proto >= CAN_NPROTO) {
> + printk(KERN_ERR "can: protocol number %d out of range\n",
> + proto);
> + return -EINVAL;
> + }
> +
> + spin_lock(&proto_tab_lock);
> + if (proto_tab[proto]) {
> + printk(KERN_ERR "can: protocol %d already registered\n",
> + proto);
> + err = -EBUSY;
> + goto errout;
> + }
> +
> + err = proto_register(cp->prot, 0);
> + if (err < 0)
> + goto errout;
> +
> + proto_tab[proto] = cp;
> +
> + /* use generic ioctl function if the module doesn't bring its own */
> + if (!cp->ops->ioctl)
> + cp->ops->ioctl = can_ioctl;
> +
> + errout:
> + spin_unlock(&proto_tab_lock);
> +
> + return err;
> +}
> +EXPORT_SYMBOL(can_proto_register);
> +
> +/**
> + * can_proto_unregister - unregister CAN transport protocol
> + * @cp: pointer to CAN protocol structure
> + */
> +void can_proto_unregister(struct can_proto *cp)
> +{
> + int proto = cp->protocol;
> +
> + spin_lock(&proto_tab_lock);
> + if (!proto_tab[proto]) {
> + printk(KERN_ERR "BUG: can: protocol %d is not registered\n",
> + proto);
> + }
> + proto_unregister(cp->prot);
> + proto_tab[proto] = NULL;
> + spin_unlock(&proto_tab_lock);
> +}
> +EXPORT_SYMBOL(can_proto_unregister);
> +
> +/*
> + * af_can notifier to create/remove CAN netdevice specific structs
> + */
> +static int can_notifier(struct notifier_block *nb, unsigned long msg,
> + void *data)
> +{
> + struct net_device *dev = (struct net_device *)data;
> + struct dev_rcv_lists *d;
> +
> + DBG("msg %ld for dev %p (%s idx %d)\n",
> + msg, dev, dev->name, dev->ifindex);
> +
> + if (dev->nd_net != &init_net)
> + return NOTIFY_DONE;
> +
> + if (dev->type != ARPHRD_CAN)
> + return NOTIFY_DONE;
> +
> + switch (msg) {
> +
> + case NETDEV_REGISTER:
> +
> + /*
> + * create new dev_rcv_lists for this device
> + *
> + * N.B. zeroing the struct is the correct initialization
> + * for the embedded hlist_head structs.
> + * Another list type, e.g. list_head, would require
> + * explicit initialization.
> + */
> +
> + DBG("creating new dev_rcv_lists for %s\n", dev->name);
> +
> + d = kzalloc(sizeof(*d), GFP_KERNEL);
> + if (!d) {
> + printk(KERN_ERR
> + "can: allocation of receive list failed\n");
> + return NOTIFY_DONE;
> + }
> + d->dev = dev;
> +
> + spin_lock(&rcv_lists_lock);
> + hlist_add_head_rcu(&d->list, &rx_dev_list);
> + spin_unlock(&rcv_lists_lock);
> +
> + break;
> +
> + case NETDEV_UNREGISTER:
> + spin_lock(&rcv_lists_lock);
> +
> + d = find_dev_rcv_lists(dev);
> + if (d) {
> + DBG("remove dev_rcv_list for %s (%d entries)\n",
> + dev->name, d->entries);
> +
> + if (d->entries) {
> + d->remove_on_zero_entries = 1;
> + d = NULL;
> + } else
> + hlist_del_rcu(&d->list);
> + } else
> + printk(KERN_ERR "can: notifier: receive list not "
> + "found for dev %s\n", dev->name);
> +
> + spin_unlock(&rcv_lists_lock);
> +
> + if (d)
> + call_rcu(&d->rcu, can_rx_delete_device);
> +
> + break;
> + }
> +
> + return NOTIFY_DONE;
> +}
> +
> +/*
> + * af_can debugging stuff
> + */
> +
> +#ifdef CONFIG_CAN_DEBUG_CORE
> +
> +/**
> + * can_debug_cframe - print CAN frame
> + * @msg: pointer to message printed before the given CAN frame
> + * @cf: pointer to CAN frame
> + */
> +void can_debug_cframe(const char *msg, struct can_frame *cf)
> +{
> + char idbuf[12];
> + char hexbuf[28];
> + int dlc;
> +
> + dlc = cf->can_dlc;
> + if (dlc > 8)
> + dlc = 8;
> +
> + if (cf->can_id & CAN_EFF_FLAG)
> + sprintf(idbuf, "<%08X>", cf->can_id & CAN_EFF_MASK);
> + else
> + sprintf(idbuf, "<%03X>", cf->can_id & CAN_SFF_MASK);
> +
> + if (cf->can_id & CAN_RTR_FLAG)
> + sprintf(hexbuf, "(RTR)");
> + else
> + hex_dump_to_buffer(cf->data, dlc, 16, 1, hexbuf, 28, 0);
> +
> + printk(KERN_DEBUG "%s: %s [%d] %s\n", msg, idbuf, dlc, hexbuf);
> +}
> +EXPORT_SYMBOL(can_debug_cframe);
> +
> +/**
> + * can_debug_skb - print socket buffer content to kernel log
> + * @skb: pointer to socket buffer
> + */
> +void can_debug_skb(struct sk_buff *skb)
> +{
> + printk(KERN_DEBUG " skbuff at %p, dev: %d, proto: %04x\n"
> + KERN_DEBUG " users: %d, dataref: %d, nr_frags: %d, "
> + "h,d,t,e,l: %p %+d %+d %+d, %d\n",
> + skb, skb->dev ? skb->dev->ifindex : -1,
> + ntohs(skb->protocol),
> + atomic_read(&skb->users),
> + atomic_read(&(skb_shinfo(skb)->dataref)),
> + skb_shinfo(skb)->nr_frags,
> + skb->head, skb->data - skb->head,
> + skb->tail - skb->head, skb->end - skb->head, skb->len);
> +
> + print_hex_dump(KERN_DEBUG, "skb_head: ", DUMP_PREFIX_NONE,
> + 16, 1, skb->head, skb->end - skb->head, 0);
> +}
> +EXPORT_SYMBOL(can_debug_skb);
> +
> +#endif
> +
> +/*
> + * af_can module init/exit functions
> + */
> +
> +static struct packet_type can_packet __read_mostly = {
> + .type = __constant_htons(ETH_P_CAN),
> + .dev = NULL,
> + .func = can_rcv,
> +};
> +
> +static struct net_proto_family can_family_ops __read_mostly = {
> + .family = PF_CAN,
> + .create = can_create,
> + .owner = THIS_MODULE,
> +};
> +
> +/* notifier block for netdevice event */
> +static struct notifier_block can_netdev_notifier __read_mostly = {
> + .notifier_call = can_notifier,
> +};
> +
> +static __init int can_init(void)
> +{
> + printk(banner);
> +
> + rcv_cache = kmem_cache_create("can_receiver", sizeof(struct receiver),
> + 0, 0, NULL);
> + if (!rcv_cache)
> + return -ENOMEM;
> +
> + /*
> + * Insert rx_alldev_list for reception on all devices.
> + * This struct is zero initialized which is correct for the
> + * embedded hlist heads, the dev pointer, and the entries counter.
> + */
> +
> + spin_lock(&rcv_lists_lock);
> + hlist_add_head_rcu(&rx_alldev_list.list, &rx_dev_list);
> + spin_unlock(&rcv_lists_lock);
> +
> + if (stats_timer) {
> + /* the statistics are updated every second (timer triggered) */
> + init_timer(&stattimer);
> + stattimer.function = can_stat_update;
> + stattimer.data = 0;
> + /* update every second */
> + stattimer.expires = round_jiffies(jiffies + HZ);
> + /* start statistics timer */
> + add_timer(&stattimer);
> + } else
> + stattimer.function = NULL;
> +
> + can_init_proc();
> +
> + /* protocol register */
> + sock_register(&can_family_ops);
> + register_netdevice_notifier(&can_netdev_notifier);
> + dev_add_pack(&can_packet);
> +
> + return 0;
> +}
> +
> +static __exit void can_exit(void)
> +{
> + struct dev_rcv_lists *d;
> + struct hlist_node *n, *next;
> +
> + if (stats_timer)
> + del_timer(&stattimer);
> +
> + can_remove_proc();
> +
> + /* protocol unregister */
> + dev_remove_pack(&can_packet);
> + unregister_netdevice_notifier(&can_netdev_notifier);
> + sock_unregister(PF_CAN);
> +
> + /* remove rx_dev_list */
> + spin_lock(&rcv_lists_lock);
> + hlist_del(&rx_alldev_list.list);
> + hlist_for_each_entry_safe(d, n, next, &rx_dev_list, list) {
> + hlist_del(&d->list);
> + kfree(d);
> + }
> + spin_unlock(&rcv_lists_lock);
> +
> + kmem_cache_destroy(rcv_cache);
> +}
> +
> +module_init(can_init);
> +module_exit(can_exit);
> Index: net-2.6.25/net/can/af_can.h
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ net-2.6.25/net/can/af_can.h 2007-11-14 13:04:49.000000000 +0100
> @@ -0,0 +1,120 @@
> +/*
> + * 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.
> + *
> + * Send feedback to <socketcan-users@...ts.berlios.de>
> + *
> + */
> +
> +#ifndef AF_CAN_H
> +#define AF_CAN_H
> +
> +#include <linux/skbuff.h>
> +#include <linux/netdevice.h>
> +#include <linux/list.h>
> +#include <linux/rcupdate.h>
> +#include <linux/can.h>
> +
> +/* af_can rx dispatcher structures */
> +
> +struct receiver {
> + struct hlist_node list;
> + struct rcu_head rcu;
> + canid_t can_id;
> + canid_t mask;
> + unsigned long matches;
> + void (*func)(struct sk_buff *, void *);
> + void *data;
> + char *ident;
> +};
> +
> +enum { RX_ERR, RX_ALL, RX_FIL, RX_INV, RX_EFF, RX_MAX };
> +
> +struct dev_rcv_lists {
> + struct hlist_node list;
> + struct rcu_head rcu;
> + struct net_device *dev;
> + struct hlist_head rx[RX_MAX];
> + struct hlist_head rx_sff[0x800];
> + int remove_on_zero_entries;
> + int entries;
> +};
> +
> +/* statistic structures */
> +
> +struct s_stats {
> + unsigned long jiffies_init;
> +
> + unsigned long rx_frames;
> + unsigned long tx_frames;
> + unsigned long matches;
> +
> + unsigned long total_rx_rate;
> + unsigned long total_tx_rate;
> + unsigned long total_rx_match_ratio;
> +
> + unsigned long current_rx_rate;
> + unsigned long current_tx_rate;
> + unsigned long current_rx_match_ratio;
> +
> + unsigned long max_rx_rate;
> + unsigned long max_tx_rate;
> + unsigned long max_rx_match_ratio;
> +
> + unsigned long rx_frames_delta;
> + unsigned long tx_frames_delta;
> + unsigned long matches_delta;
> +}; /* can be reset e.g. by can_init_stats() */
> +
> +struct s_pstats {
> + unsigned long stats_reset;
> + unsigned long user_reset;
> + unsigned long rcv_entries;
> + unsigned long rcv_entries_max;
> +}; /* persistent statistics */
> +
> +/* function prototypes for the CAN networklayer procfs (proc.c) */
> +extern void can_init_proc(void);
> +extern void can_remove_proc(void);
> +extern void can_stat_update(unsigned long data);
> +
> +/* structures and variables from af_can.c needed in proc.c for reading */
> +extern struct timer_list stattimer; /* timer for statistics update */
> +extern struct s_stats stats; /* packet statistics */
> +extern struct s_pstats pstats; /* receive list statistics */
> +extern struct hlist_head rx_dev_list; /* rx dispatcher structures */
> +
> +#endif /* AF_CAN_H */
> Index: net-2.6.25/net/can/proc.c
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ net-2.6.25/net/can/proc.c 2007-11-14 13:04:49.000000000 +0100
> @@ -0,0 +1,532 @@
> +/*
> + * proc.c - procfs support for Protocol family CAN core module
> + *
> + * 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.
> + *
> + * Send feedback to <socketcan-users@...ts.berlios.de>
> + *
> + */
> +
> +#include <linux/module.h>
> +#include <linux/proc_fs.h>
> +#include <linux/list.h>
> +#include <linux/rcupdate.h>
> +#include <linux/can/core.h>
> +
> +#include "af_can.h"
> +
> +/*
> + * proc filenames for the PF_CAN core
> + */
> +
> +#define CAN_PROC_VERSION "version"
> +#define CAN_PROC_STATS "stats"
> +#define CAN_PROC_RESET_STATS "reset_stats"
> +#define CAN_PROC_RCVLIST_ALL "rcvlist_all"
> +#define CAN_PROC_RCVLIST_FIL "rcvlist_fil"
> +#define CAN_PROC_RCVLIST_INV "rcvlist_inv"
> +#define CAN_PROC_RCVLIST_SFF "rcvlist_sff"
> +#define CAN_PROC_RCVLIST_EFF "rcvlist_eff"
> +#define CAN_PROC_RCVLIST_ERR "rcvlist_err"
> +
> +static struct proc_dir_entry *can_dir;
> +static struct proc_dir_entry *pde_version;
> +static struct proc_dir_entry *pde_stats;
> +static struct proc_dir_entry *pde_reset_stats;
> +static struct proc_dir_entry *pde_rcvlist_all;
> +static struct proc_dir_entry *pde_rcvlist_fil;
> +static struct proc_dir_entry *pde_rcvlist_inv;
> +static struct proc_dir_entry *pde_rcvlist_sff;
> +static struct proc_dir_entry *pde_rcvlist_eff;
> +static struct proc_dir_entry *pde_rcvlist_err;
> +
> +static int user_reset;
> +
> +static const char rx_list_name[][8] = {
> + [RX_ERR] = "rx_err",
> + [RX_ALL] = "rx_all",
> + [RX_FIL] = "rx_fil",
> + [RX_INV] = "rx_inv",
> + [RX_EFF] = "rx_eff",
> +};
> +
> +/*
> + * af_can statistics stuff
> + */
> +
> +static void can_init_stats(void)
> +{
> + /*
> + * This memset function is called from a timer context (when
> + * stattimer is active which is the default) OR in a process
> + * context (reading the proc_fs when stattimer is disabled).
> + */
> + memset(&stats, 0, sizeof(stats));
> + stats.jiffies_init = jiffies;
> +
> + pstats.stats_reset++;
> +
> + if (user_reset) {
> + user_reset = 0;
> + pstats.user_reset++;
> + }
> +}
> +
> +static unsigned long calc_rate(unsigned long oldjif, unsigned long newjif,
> + unsigned long count)
> +{
> + unsigned long rate;
> +
> + if (oldjif == newjif)
> + return 0;
> +
> + /* see can_stat_update() - this should NEVER happen! */
> + if (count > (ULONG_MAX / HZ)) {
> + printk(KERN_ERR "can: calc_rate: count exceeded! %ld\n",
> + count);
> + return 99999999;
> + }
> +
> + rate = (count * HZ) / (newjif - oldjif);
> +
> + return rate;
> +}
> +
> +void can_stat_update(unsigned long data)
> +{
> + unsigned long j = jiffies; /* snapshot */
> +
> + /* restart counting in timer context on user request */
> + if (user_reset)
> + can_init_stats();
> +
> + /* restart counting on jiffies overflow */
> + if (j < stats.jiffies_init)
> + can_init_stats();
> +
> + /* prevent overflow in calc_rate() */
> + if (stats.rx_frames > (ULONG_MAX / HZ))
> + can_init_stats();
> +
> + /* prevent overflow in calc_rate() */
> + if (stats.tx_frames > (ULONG_MAX / HZ))
> + can_init_stats();
> +
> + /* matches overflow - very improbable */
> + if (stats.matches > (ULONG_MAX / 100))
> + can_init_stats();
> +
> + /* calc total values */
> + if (stats.rx_frames)
> + stats.total_rx_match_ratio = (stats.matches * 100) /
> + stats.rx_frames;
> +
> + stats.total_tx_rate = calc_rate(stats.jiffies_init, j,
> + stats.tx_frames);
> + stats.total_rx_rate = calc_rate(stats.jiffies_init, j,
> + stats.rx_frames);
> +
> + /* calc current values */
> + if (stats.rx_frames_delta)
> + stats.current_rx_match_ratio =
> + (stats.matches_delta * 100) / stats.rx_frames_delta;
> +
> + stats.current_tx_rate = calc_rate(0, HZ, stats.tx_frames_delta);
> + stats.current_rx_rate = calc_rate(0, HZ, stats.rx_frames_delta);
> +
> + /* check / update maximum values */
> + if (stats.max_tx_rate < stats.current_tx_rate)
> + stats.max_tx_rate = stats.current_tx_rate;
> +
> + if (stats.max_rx_rate < stats.current_rx_rate)
> + stats.max_rx_rate = stats.current_rx_rate;
> +
> + if (stats.max_rx_match_ratio < stats.current_rx_match_ratio)
> + stats.max_rx_match_ratio = stats.current_rx_match_ratio;
> +
> + /* clear values for 'current rate' calculation */
> + stats.tx_frames_delta = 0;
> + stats.rx_frames_delta = 0;
> + stats.matches_delta = 0;
> +
> + /* restart timer (one second) */
> + stattimer.expires = round_jiffies(jiffies + HZ);
> + add_timer(&stattimer);
> +}
> +
> +/*
> + * proc read functions
> + *
> + * From known use-cases we expect about 10 entries in a receive list to be
> + * printed in the proc_fs. So PAGE_SIZE is definitely enough space here.
> + *
> + */
> +
> +static int can_print_rcvlist(char *page, int len, struct hlist_head *rx_list,
> + struct net_device *dev)
> +{
> + struct receiver *r;
> + struct hlist_node *n;
> +
> + rcu_read_lock();
> + hlist_for_each_entry_rcu(r, n, rx_list, list) {
> + char *fmt = (r->can_id & CAN_EFF_FLAG)?
> + " %-5s %08X %08x %08x %08x %8ld %s\n" :
> + " %-5s %03X %08x %08lx %08lx %8ld %s\n";
> +
> + len += snprintf(page + len, PAGE_SIZE - len, fmt,
> + DNAME(dev), r->can_id, r->mask,
> + (unsigned long)r->func, (unsigned long)r->data,
> + r->matches, r->ident);
> +
> + /* does a typical line fit into the current buffer? */
> +
> + /* 100 Bytes before end of buffer */
> + if (len > PAGE_SIZE - 100) {
> + /* mark output cut off */
> + len += snprintf(page + len, PAGE_SIZE - len,
> + " (..)\n");
> + break;
> + }
> + }
> + rcu_read_unlock();
> +
> + return len;
> +}
> +
> +static int can_print_recv_banner(char *page, int len)
> +{
> + /*
> + * can1. 00000000 00000000 00000000
> + * ....... 0 tp20
> + */
> + len += snprintf(page + len, PAGE_SIZE - len,
> + " device can_id can_mask function"
> + " userdata matches ident\n");
> +
> + return len;
> +}
> +
> +static int can_proc_read_stats(char *page, char **start, off_t off,
> + int count, int *eof, void *data)
> +{
> + int len = 0;
> +
> + len += snprintf(page + len, PAGE_SIZE - len, "\n");
> + len += snprintf(page + len, PAGE_SIZE - len,
> + " %8ld transmitted frames (TXF)\n", stats.tx_frames);
> + len += snprintf(page + len, PAGE_SIZE - len,
> + " %8ld received frames (RXF)\n", stats.rx_frames);
> + len += snprintf(page + len, PAGE_SIZE - len,
> + " %8ld matched frames (RXMF)\n", stats.matches);
> +
> + len += snprintf(page + len, PAGE_SIZE - len, "\n");
> +
> + if (stattimer.function == can_stat_update) {
> + len += snprintf(page + len, PAGE_SIZE - len,
> + " %8ld %% total match ratio (RXMR)\n",
> + stats.total_rx_match_ratio);
> +
> + len += snprintf(page + len, PAGE_SIZE - len,
> + " %8ld frames/s total tx rate (TXR)\n",
> + stats.total_tx_rate);
> + len += snprintf(page + len, PAGE_SIZE - len,
> + " %8ld frames/s total rx rate (RXR)\n",
> + stats.total_rx_rate);
> +
> + len += snprintf(page + len, PAGE_SIZE - len, "\n");
> +
> + len += snprintf(page + len, PAGE_SIZE - len,
> + " %8ld %% current match ratio (CRXMR)\n",
> + stats.current_rx_match_ratio);
> +
> + len += snprintf(page + len, PAGE_SIZE - len,
> + " %8ld frames/s current tx rate (CTXR)\n",
> + stats.current_tx_rate);
> + len += snprintf(page + len, PAGE_SIZE - len,
> + " %8ld frames/s current rx rate (CRXR)\n",
> + stats.current_rx_rate);
> +
> + len += snprintf(page + len, PAGE_SIZE - len, "\n");
> +
> + len += snprintf(page + len, PAGE_SIZE - len,
> + " %8ld %% max match ratio (MRXMR)\n",
> + stats.max_rx_match_ratio);
> +
> + len += snprintf(page + len, PAGE_SIZE - len,
> + " %8ld frames/s max tx rate (MTXR)\n",
> + stats.max_tx_rate);
> + len += snprintf(page + len, PAGE_SIZE - len,
> + " %8ld frames/s max rx rate (MRXR)\n",
> + stats.max_rx_rate);
> +
> + len += snprintf(page + len, PAGE_SIZE - len, "\n");
> + }
> +
> + len += snprintf(page + len, PAGE_SIZE - len,
> + " %8ld current receive list entries (CRCV)\n",
> + pstats.rcv_entries);
> + len += snprintf(page + len, PAGE_SIZE - len,
> + " %8ld maximum receive list entries (MRCV)\n",
> + pstats.rcv_entries_max);
> +
> + if (pstats.stats_reset)
> + len += snprintf(page + len, PAGE_SIZE - len,
> + "\n %8ld statistic resets (STR)\n",
> + pstats.stats_reset);
> +
> + if (pstats.user_reset)
> + len += snprintf(page + len, PAGE_SIZE - len,
> + " %8ld user statistic resets (USTR)\n",
> + pstats.user_reset);
> +
> + len += snprintf(page + len, PAGE_SIZE - len, "\n");
> +
> + *eof = 1;
> + return len;
> +}
The read interface should use seq_file interface rather than
formatting into page buffer.
> +static int can_proc_read_reset_stats(char *page, char **start, off_t off,
> + int count, int *eof, void *data)
> +{
> + int len = 0;
> +
> + user_reset = 1;
> +
> + if (stattimer.function == can_stat_update) {
> + len += snprintf(page + len, PAGE_SIZE - len,
> + "Scheduled statistic reset #%ld.\n",
> + pstats.stats_reset + 1);
> +
> + } else {
> + if (stats.jiffies_init != jiffies)
> + can_init_stats();
> +
> + len += snprintf(page + len, PAGE_SIZE - len,
> + "Performed statistic reset #%ld.\n",
> + pstats.stats_reset);
> + }
> +
> + *eof = 1;
> + return len;
> +}
Why not have a write interface to do the reset?
> +static int can_proc_read_version(char *page, char **start, off_t off,
> + int count, int *eof, void *data)
> +{
> + int len = 0;
> +
> + len += snprintf(page + len, PAGE_SIZE - len, "%s\n",
> + CAN_VERSION_STRING);
> + *eof = 1;
> + return len;
> +}
> +
> +static int can_proc_read_rcvlist(char *page, char **start, off_t off,
> + int count, int *eof, void *data)
> +{
> + /* double cast to prevent GCC warning */
> + int idx = (int)(long)data;
> + int len = 0;
> + struct dev_rcv_lists *d;
> + struct hlist_node *n;
> +
> + len += snprintf(page + len, PAGE_SIZE - len,
> + "\nreceive list '%s':\n", rx_list_name[idx]);
> +
> + rcu_read_lock();
> + hlist_for_each_entry_rcu(d, n, &rx_dev_list, list) {
> +
> + if (!hlist_empty(&d->rx[idx])) {
> + len = can_print_recv_banner(page, len);
> + len = can_print_rcvlist(page, len, &d->rx[idx], d->dev);
> + } else
> + len += snprintf(page + len, PAGE_SIZE - len,
> + " (%s: no entry)\n", DNAME(d->dev));
> +
> + /* exit on end of buffer? */
> + if (len > PAGE_SIZE - 100)
> + break;
> + }
> + rcu_read_unlock();
> +
> + len += snprintf(page + len, PAGE_SIZE - len, "\n");
> +
> + *eof = 1;
> + return len;
> +}
> +
> +static int can_proc_read_rcvlist_sff(char *page, char **start, off_t off,
> + int count, int *eof, void *data)
> +{
> + int len = 0;
> + struct dev_rcv_lists *d;
> + struct hlist_node *n;
> +
> + /* RX_SFF */
> + len += snprintf(page + len, PAGE_SIZE - len,
> + "\nreceive list 'rx_sff':\n");
> +
> + rcu_read_lock();
> + hlist_for_each_entry_rcu(d, n, &rx_dev_list, list) {
> + int i, all_empty = 1;
> + /* check wether at least one list is non-empty */
> + for (i = 0; i < 0x800; i++)
> + if (!hlist_empty(&d->rx_sff[i])) {
> + all_empty = 0;
> + break;
> + }
> +
> + if (!all_empty) {
> + len = can_print_recv_banner(page, len);
> + for (i = 0; i < 0x800; i++) {
> + if (!hlist_empty(&d->rx_sff[i]) &&
> + len < PAGE_SIZE - 100)
> + len = can_print_rcvlist(page, len,
> + &d->rx_sff[i],
> + d->dev);
> + }
> + } else
> + len += snprintf(page + len, PAGE_SIZE - len,
> + " (%s: no entry)\n", DNAME(d->dev));
> +
> + /* exit on end of buffer? */
> + if (len > PAGE_SIZE - 100)
> + break;
> + }
> + rcu_read_unlock();
> +
> + len += snprintf(page + len, PAGE_SIZE - len, "\n");
> +
> + *eof = 1;
> + return len;
> +}
> +
> +/*
> + * proc utility functions
> + */
> +
> +static struct proc_dir_entry *can_create_proc_readentry(const char *name,
> + mode_t mode,
> + read_proc_t *read_proc,
> + void *data)
> +{
> + if (can_dir)
> + return create_proc_read_entry(name, mode, can_dir, read_proc,
> + data);
> + else
> + return NULL;
> +}
> +
> +static void can_remove_proc_readentry(const char *name)
> +{
> + if (can_dir)
> + remove_proc_entry(name, can_dir);
> +}
> +
> +/*
> + * can_init_proc - create main CAN proc directory and procfs entries
> + */
> +void can_init_proc(void)
> +{
> + /* create /proc/net/can directory */
> + can_dir = proc_mkdir("can", init_net.proc_net);
> +
> + if (!can_dir) {
> + printk(KERN_INFO "can: failed to create /proc/net/can . "
> + "CONFIG_PROC_FS missing?\n");
> + return;
> + }
> +
> + can_dir->owner = THIS_MODULE;
> +
> + /* own procfs entries from the AF_CAN core */
> + pde_version = can_create_proc_readentry(CAN_PROC_VERSION, 0644,
> + can_proc_read_version, NULL);
> + pde_stats = can_create_proc_readentry(CAN_PROC_STATS, 0644,
> + can_proc_read_stats, NULL);
> + pde_reset_stats = can_create_proc_readentry(CAN_PROC_RESET_STATS, 0644,
> + can_proc_read_reset_stats, NULL);
> + pde_rcvlist_err = can_create_proc_readentry(CAN_PROC_RCVLIST_ERR, 0644,
> + can_proc_read_rcvlist, (void *)RX_ERR);
> + pde_rcvlist_all = can_create_proc_readentry(CAN_PROC_RCVLIST_ALL, 0644,
> + can_proc_read_rcvlist, (void *)RX_ALL);
> + pde_rcvlist_fil = can_create_proc_readentry(CAN_PROC_RCVLIST_FIL, 0644,
> + can_proc_read_rcvlist, (void *)RX_FIL);
> + pde_rcvlist_inv = can_create_proc_readentry(CAN_PROC_RCVLIST_INV, 0644,
> + can_proc_read_rcvlist, (void *)RX_INV);
> + pde_rcvlist_eff = can_create_proc_readentry(CAN_PROC_RCVLIST_EFF, 0644,
> + can_proc_read_rcvlist, (void *)RX_EFF);
> + pde_rcvlist_sff = can_create_proc_readentry(CAN_PROC_RCVLIST_SFF, 0644,
> + can_proc_read_rcvlist_sff, NULL);
> +}
> +
> +/*
> + * can_remove_proc - remove procfs entries and main CAN proc directory
> + */
> +void can_remove_proc(void)
> +{
> + if (pde_version)
> + can_remove_proc_readentry(CAN_PROC_VERSION);
> +
> + if (pde_stats)
> + can_remove_proc_readentry(CAN_PROC_STATS);
> +
> + if (pde_reset_stats)
> + can_remove_proc_readentry(CAN_PROC_RESET_STATS);
> +
> + if (pde_rcvlist_err)
> + can_remove_proc_readentry(CAN_PROC_RCVLIST_ERR);
> +
> + if (pde_rcvlist_all)
> + can_remove_proc_readentry(CAN_PROC_RCVLIST_ALL);
> +
> + if (pde_rcvlist_fil)
> + can_remove_proc_readentry(CAN_PROC_RCVLIST_FIL);
> +
> + if (pde_rcvlist_inv)
> + can_remove_proc_readentry(CAN_PROC_RCVLIST_INV);
> +
> + if (pde_rcvlist_eff)
> + can_remove_proc_readentry(CAN_PROC_RCVLIST_EFF);
> +
> + if (pde_rcvlist_sff)
> + can_remove_proc_readentry(CAN_PROC_RCVLIST_SFF);
> +
> + if (can_dir)
> + proc_net_remove(&init_net, "can");
> +}
>
Output from checkpatch:
WARNING: do not add new typedefs
#116: FILE: include/linux/can.h:41:
+typedef __u32 canid_t;
WARNING: do not add new typedefs
#124: FILE: include/linux/can.h:49:
+typedef __u32 can_err_mask_t;
ERROR: use tabs not spaces
#498: FILE: net/can/af_can.c:159:
+^I^I^I^I " not implemented.\n", module_name);$
WARNING: braces {} are not necessary for single statement blocks
#1080: FILE: net/can/af_can.c:741:
+ if (!proto_tab[proto]) {
+ printk(KERN_ERR "BUG: can: protocol %d is not registered\n",
+ proto);
+ }
total: 1 errors, 3 warnings, 1954 lines checked
Your patch has style problems, please review. If any of these errors
are false positives report them to the maintainer, see
CHECKPATCH in MAINTAINERS.
--
Stephen Hemminger <shemminger@...ux-foundation.org>
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