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![Pablo Neira Ayuso](/assets/img/avatar_default.png)
Currently, netlink_broadcast() reports errors to the caller if no messages at all were delivered: 1) If, at least, one message has been delivered correctly, returns 0. 2) Otherwise, if no messages at all were delivered due to skb_clone() failure, return -ENOBUFS. 3) Otherwise, if there are no listeners, return -ESRCH. With this patch, the caller knows if the delivery of any of the messages to the listeners have failed: 1) If it fails to deliver any message (for whatever reason), return -ENOBUFS. 2) Otherwise, if all messages were delivered OK, returns 0. 3) Otherwise, if no listeners, return -ESRCH. In the current ctnetlink code and in Netfilter in general, we can add reliable logging and connection tracking event delivery by dropping the packets whose events were not successfully delivered over Netlink. Of course, this option would be settable via /proc as this approach reduces performance (in terms of filtered connections per seconds by a stateful firewall) but providing reliable logging and event delivery (for conntrackd) in return. This patch also changes some clients of netlink_broadcast() that may report ENOBUFS errors via printk. This error handling is not of any help. Instead, the userspace daemons that are listening to those netlink messages should resync themselves with the kernel-side if they hit ENOBUFS. BTW, netlink_broadcast() clients include those that call cn_netlink_send(), nlmsg_multicast() and genlmsg_multicast() since they internally call netlink_broadcast() and return its error value. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
303 lines
6.7 KiB
C
303 lines
6.7 KiB
C
/*
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* event.c - exporting ACPI events via procfs
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*
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* Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
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* Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
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*
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*/
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#include <linux/spinlock.h>
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#include <linux/proc_fs.h>
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#include <linux/init.h>
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#include <linux/poll.h>
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#include <acpi/acpi_drivers.h>
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#include <net/netlink.h>
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#include <net/genetlink.h>
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#define _COMPONENT ACPI_SYSTEM_COMPONENT
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ACPI_MODULE_NAME("event");
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#ifdef CONFIG_ACPI_PROC_EVENT
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/* Global vars for handling event proc entry */
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static DEFINE_SPINLOCK(acpi_system_event_lock);
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int event_is_open = 0;
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extern struct list_head acpi_bus_event_list;
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extern wait_queue_head_t acpi_bus_event_queue;
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static int acpi_system_open_event(struct inode *inode, struct file *file)
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{
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spin_lock_irq(&acpi_system_event_lock);
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if (event_is_open)
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goto out_busy;
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event_is_open = 1;
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spin_unlock_irq(&acpi_system_event_lock);
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return 0;
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out_busy:
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spin_unlock_irq(&acpi_system_event_lock);
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return -EBUSY;
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}
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static ssize_t
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acpi_system_read_event(struct file *file, char __user * buffer, size_t count,
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loff_t * ppos)
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{
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int result = 0;
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struct acpi_bus_event event;
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static char str[ACPI_MAX_STRING];
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static int chars_remaining = 0;
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static char *ptr;
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if (!chars_remaining) {
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memset(&event, 0, sizeof(struct acpi_bus_event));
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if ((file->f_flags & O_NONBLOCK)
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&& (list_empty(&acpi_bus_event_list)))
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return -EAGAIN;
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result = acpi_bus_receive_event(&event);
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if (result)
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return result;
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chars_remaining = sprintf(str, "%s %s %08x %08x\n",
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event.device_class ? event.
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device_class : "<unknown>",
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event.bus_id ? event.
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bus_id : "<unknown>", event.type,
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event.data);
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ptr = str;
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}
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if (chars_remaining < count) {
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count = chars_remaining;
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}
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if (copy_to_user(buffer, ptr, count))
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return -EFAULT;
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*ppos += count;
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chars_remaining -= count;
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ptr += count;
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return count;
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}
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static int acpi_system_close_event(struct inode *inode, struct file *file)
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{
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spin_lock_irq(&acpi_system_event_lock);
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event_is_open = 0;
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spin_unlock_irq(&acpi_system_event_lock);
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return 0;
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}
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static unsigned int acpi_system_poll_event(struct file *file, poll_table * wait)
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{
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poll_wait(file, &acpi_bus_event_queue, wait);
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if (!list_empty(&acpi_bus_event_list))
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return POLLIN | POLLRDNORM;
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return 0;
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}
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static const struct file_operations acpi_system_event_ops = {
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.owner = THIS_MODULE,
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.open = acpi_system_open_event,
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.read = acpi_system_read_event,
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.release = acpi_system_close_event,
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.poll = acpi_system_poll_event,
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};
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#endif /* CONFIG_ACPI_PROC_EVENT */
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/* ACPI notifier chain */
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static BLOCKING_NOTIFIER_HEAD(acpi_chain_head);
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int acpi_notifier_call_chain(struct acpi_device *dev, u32 type, u32 data)
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{
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struct acpi_bus_event event;
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strcpy(event.device_class, dev->pnp.device_class);
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strcpy(event.bus_id, dev->pnp.bus_id);
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event.type = type;
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event.data = data;
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return (blocking_notifier_call_chain(&acpi_chain_head, 0, (void *)&event)
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== NOTIFY_BAD) ? -EINVAL : 0;
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}
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EXPORT_SYMBOL(acpi_notifier_call_chain);
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int register_acpi_notifier(struct notifier_block *nb)
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{
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return blocking_notifier_chain_register(&acpi_chain_head, nb);
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}
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EXPORT_SYMBOL(register_acpi_notifier);
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int unregister_acpi_notifier(struct notifier_block *nb)
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{
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return blocking_notifier_chain_unregister(&acpi_chain_head, nb);
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}
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EXPORT_SYMBOL(unregister_acpi_notifier);
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#ifdef CONFIG_NET
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static unsigned int acpi_event_seqnum;
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struct acpi_genl_event {
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acpi_device_class device_class;
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char bus_id[15];
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u32 type;
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u32 data;
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};
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/* attributes of acpi_genl_family */
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enum {
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ACPI_GENL_ATTR_UNSPEC,
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ACPI_GENL_ATTR_EVENT, /* ACPI event info needed by user space */
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__ACPI_GENL_ATTR_MAX,
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};
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#define ACPI_GENL_ATTR_MAX (__ACPI_GENL_ATTR_MAX - 1)
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/* commands supported by the acpi_genl_family */
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enum {
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ACPI_GENL_CMD_UNSPEC,
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ACPI_GENL_CMD_EVENT, /* kernel->user notifications for ACPI events */
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__ACPI_GENL_CMD_MAX,
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};
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#define ACPI_GENL_CMD_MAX (__ACPI_GENL_CMD_MAX - 1)
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#define ACPI_GENL_FAMILY_NAME "acpi_event"
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#define ACPI_GENL_VERSION 0x01
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#define ACPI_GENL_MCAST_GROUP_NAME "acpi_mc_group"
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static struct genl_family acpi_event_genl_family = {
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.id = GENL_ID_GENERATE,
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.name = ACPI_GENL_FAMILY_NAME,
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.version = ACPI_GENL_VERSION,
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.maxattr = ACPI_GENL_ATTR_MAX,
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};
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static struct genl_multicast_group acpi_event_mcgrp = {
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.name = ACPI_GENL_MCAST_GROUP_NAME,
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};
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int acpi_bus_generate_netlink_event(const char *device_class,
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const char *bus_id,
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u8 type, int data)
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{
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struct sk_buff *skb;
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struct nlattr *attr;
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struct acpi_genl_event *event;
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void *msg_header;
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int size;
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int result;
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/* allocate memory */
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size = nla_total_size(sizeof(struct acpi_genl_event)) +
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nla_total_size(0);
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skb = genlmsg_new(size, GFP_ATOMIC);
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if (!skb)
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return -ENOMEM;
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/* add the genetlink message header */
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msg_header = genlmsg_put(skb, 0, acpi_event_seqnum++,
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&acpi_event_genl_family, 0,
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ACPI_GENL_CMD_EVENT);
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if (!msg_header) {
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nlmsg_free(skb);
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return -ENOMEM;
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}
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/* fill the data */
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attr =
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nla_reserve(skb, ACPI_GENL_ATTR_EVENT,
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sizeof(struct acpi_genl_event));
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if (!attr) {
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nlmsg_free(skb);
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return -EINVAL;
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}
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event = nla_data(attr);
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if (!event) {
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nlmsg_free(skb);
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return -EINVAL;
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}
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memset(event, 0, sizeof(struct acpi_genl_event));
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strcpy(event->device_class, device_class);
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strcpy(event->bus_id, bus_id);
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event->type = type;
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event->data = data;
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/* send multicast genetlink message */
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result = genlmsg_end(skb, msg_header);
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if (result < 0) {
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nlmsg_free(skb);
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return result;
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}
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genlmsg_multicast(skb, 0, acpi_event_mcgrp.id, GFP_ATOMIC);
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return 0;
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}
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EXPORT_SYMBOL(acpi_bus_generate_netlink_event);
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static int acpi_event_genetlink_init(void)
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{
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int result;
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result = genl_register_family(&acpi_event_genl_family);
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if (result)
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return result;
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result = genl_register_mc_group(&acpi_event_genl_family,
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&acpi_event_mcgrp);
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if (result)
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genl_unregister_family(&acpi_event_genl_family);
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return result;
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}
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#else
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int acpi_bus_generate_netlink_event(const char *device_class,
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const char *bus_id,
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u8 type, int data)
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{
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return 0;
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}
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EXPORT_SYMBOL(acpi_bus_generate_netlink_event);
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static int acpi_event_genetlink_init(void)
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{
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return -ENODEV;
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}
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#endif
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static int __init acpi_event_init(void)
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{
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#ifdef CONFIG_ACPI_PROC_EVENT
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struct proc_dir_entry *entry;
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#endif
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int error = 0;
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if (acpi_disabled)
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return 0;
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/* create genetlink for acpi event */
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error = acpi_event_genetlink_init();
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if (error)
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printk(KERN_WARNING PREFIX
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"Failed to create genetlink family for ACPI event\n");
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#ifdef CONFIG_ACPI_PROC_EVENT
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/* 'event' [R] */
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entry = proc_create("event", S_IRUSR, acpi_root_dir,
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&acpi_system_event_ops);
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if (!entry)
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return -ENODEV;
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#endif
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return 0;
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}
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fs_initcall(acpi_event_init);
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