/*
 * netsniff-ng - the packet sniffing beast
 * Copyright 2012 Daniel Borkmann.
 * Subject to the GPL, version 2.
 * Parts derived from iw, subject to ISC license.
 * Copyright 2007, 2008	Johannes Berg
 * Copyright 2007 Andy Lutomirski
 * Copyright 2007 Mike Kershaw
 * Copyright 2008-2009 Luis R. Rodriguez
 */

#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <limits.h>
#include <sys/socket.h>
#include <linux/if.h>
#include <linux/nl80211.h>
#include <netlink/genl/genl.h>
#include <netlink/genl/family.h>
#include <netlink/genl/ctrl.h>
#include <netlink/msg.h>
#include <netlink/attr.h>

#include "str.h"
#include "dev.h"
#include "mac80211.h"
#include "xmalloc.h"
#include "built_in.h"

struct nl80211_state {
	struct nl_sock *nl_sock;
	struct nl_cache *nl_cache;
	struct genl_family *nl80211;
};

static void get_mac80211_phydev(const char *device, char *phydev_path,
				size_t phydev_len)
{
	int ret;
	char *pathstr;
	ssize_t num;

	ret = asprintf(&pathstr, "/sys/class/net/%s/phy80211", device);
	if (ret < 0)
		panic("Can't generate path name string for /sys/class/net device");

	num = readlink(pathstr, phydev_path, phydev_len);
	if (num < 0) {
		if (errno == ENOENT || errno == EINVAL)
			panic("It's probably not a mac80211 device!\n");
		panic("Can't readlink %s: %s!\n", pathstr, strerror(errno));
	}

	xfree(pathstr);
	phydev_path[min_t(size_t, num, phydev_len - 1)] = 0;
}

static inline struct nl_msg *nl80211_nlmsg_xalloc(void)
{
	struct nl_msg *ret = nlmsg_alloc();
	if (!ret)
		panic("Cannot allocate nlmsg memory!\n");
	return ret;
}

static inline struct nl_sock *nl80211_nl_socket_xalloc(void)
{
	struct nl_sock *ret = nl_socket_alloc();
	if (!ret)
		panic("Cannot allocate nl socket memory!\n");
	return ret;
}

static void nl80211_init(struct nl80211_state *state)
{
	int ret;

	state->nl_sock = nl80211_nl_socket_xalloc();

	ret = genl_connect(state->nl_sock);
	if (ret)
		panic("Cannot connect generic netlink!\n");

	ret = genl_ctrl_alloc_cache(state->nl_sock, &state->nl_cache);
	if (ret < 0)
		panic("Failed to allocate generic netlink cache: %s!",
		      nl_geterror(-ret));

	state->nl80211 = genl_ctrl_search_by_name(state->nl_cache, "nl80211");
	if (!state->nl80211)
		panic("nl80211 not found in netlink cache!\n");
}

static void nl80211_cleanup(struct nl80211_state *state)
{
	genl_family_put(state->nl80211);

	nl_cache_free(state->nl_cache);
	nl_socket_free(state->nl_sock);
}

static int nl80211_wait_handler(struct nl_msg *msg __maybe_unused, void *arg)
{
	int *finished = arg;

	*finished = 1;

	return NL_STOP;
}

static int nl80211_error_handler(struct sockaddr_nl *nla __maybe_unused,
				 struct nlmsgerr *err,
				 void *arg __maybe_unused)
{
	panic("nl80211 returned with error (%d): %s\n", err->error,
	      nl_geterror(err->error));
}

static int nl80211_add_mon_if(struct nl80211_state *state, const char *device,
			      const char *mondevice)
{
	int ifindex, ret;
	struct nl_msg *msg;
	struct nl_cb *cb = NULL;
	int finished = 0;

	ifindex = device_ifindex(device);

	msg = nl80211_nlmsg_xalloc();

	genlmsg_put(msg, 0, 0, genl_family_get_id(state->nl80211), 0,
		    0, NL80211_CMD_NEW_INTERFACE, 0);

	NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, ifindex);
	NLA_PUT_STRING(msg, NL80211_ATTR_IFNAME, mondevice);
	NLA_PUT_U32(msg, NL80211_ATTR_IFTYPE, NL80211_IFTYPE_MONITOR);

	ret = nl_send_auto_complete(state->nl_sock, msg);
	if (ret < 0) {
		if (ret == -ENFILE) {
			nlmsg_free(msg);
			return -EBUSY;
		}

		panic("Cannot send_auto_complete!\n");
	}

	cb = nl_cb_alloc(NL_CB_CUSTOM);
	if (!cb)
		panic("Cannot alloc nl_cb!\n");

	nl_cb_set(cb, NL_CB_ACK, NL_CB_CUSTOM, nl80211_wait_handler, &finished);
	nl_cb_err(cb, NL_CB_CUSTOM, nl80211_error_handler, NULL);

	nl_recvmsgs(state->nl_sock, cb);

	if (!finished) {
		ret = nl_wait_for_ack(state->nl_sock);
		if (ret < 0) {
			if (ret == -ENFILE) {
				nlmsg_free(msg);
				return -EBUSY;
			}

			panic("Waiting for netlink ack failed!\n");
		}
	}

	nl_cb_put(cb);
	nlmsg_free(msg);
	return 0;

nla_put_failure:
	panic("nla put failure!\n");
	return -EIO; /* dummy */
}

static int nl80211_del_mon_if(struct nl80211_state *state,
			      const char *mondevice)
{
	int ifindex, ret;
	struct nl_msg *msg;

	ifindex = device_ifindex(mondevice);

	msg = nl80211_nlmsg_xalloc();

	genlmsg_put(msg, 0, 0, genl_family_get_id(state->nl80211), 0,
		    0, NL80211_CMD_DEL_INTERFACE, 0);

	NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, ifindex);

	ret = nl_send_auto_complete(state->nl_sock, msg);
	if (ret < 0)
		panic("Cannot send_auto_complete!\n");

	ret = nl_wait_for_ack(state->nl_sock);
	if (ret < 0)
		panic("Waiting for netlink ack failed!\n");

	nlmsg_free(msg);
	return 0;

nla_put_failure:
	panic("nla put failure!\n");
	return -EIO; /* dummy */
}

void enter_rfmon_mac80211(const char *device, char **mondev)
{
	int ret;
	short flags;
	uint32_t n;
	char phydev_path[256];
	struct nl80211_state nlstate;

	/* XXX: is this already a monN device? */
	get_mac80211_phydev(device, phydev_path, sizeof(phydev_path));
	nl80211_init(&nlstate);

	for (n = 0; n < UINT_MAX; n++) {
		char mondevice[32];

		slprintf(mondevice, sizeof(mondevice), "mon%u", n);

		if (__device_ifindex(mondevice) > 0)
			continue;

		ret = nl80211_add_mon_if(&nlstate, device, mondevice);
		if (ret == 0) {
			*mondev = xstrdup(mondevice);

			flags = device_get_flags(*mondev);
			flags |= IFF_UP | IFF_RUNNING;
			device_set_flags(*mondev, flags);

			nl80211_cleanup(&nlstate);
			return;
		}
	}

	panic("No free monN interfaces!\n");
}

void leave_rfmon_mac80211(const char *mondev)
{
	short flags;
	struct nl80211_state nlstate;

	flags = device_get_flags(mondev);
	flags &= ~(IFF_UP | IFF_RUNNING);
	device_set_flags(mondev, flags);

	nl80211_init(&nlstate);
	nl80211_del_mon_if(&nlstate, mondev);
	nl80211_cleanup(&nlstate);
}
lass='commit-subject'>cpuidle: Fix cpuidle_state_is_coupled() argument in cpuidle_enter()</div><div class='commit-msg'>Commit 0b89e9aa2856 (cpuidle: delay enabling interrupts until all
coupled CPUs leave idle) rightfully fixed a regression by letting
the coupled idle state framework to handle local interrupt enabling
when the CPU is exiting an idle state.

The current code checks if the idle state is coupled and, if so, it
will let the coupled code to enable interrupts. This way, it can
decrement the ready-count before handling the interrupt. This
mechanism prevents the other CPUs from waiting for a CPU which is
handling interrupts.

But the check is done against the state index returned by the back
end driver's -&gt;enter functions which could be different from the
initial index passed as parameter to the cpuidle_enter_state()
function.

 entered_state = target_state-&gt;enter(dev, drv, index);

 [ ... ]

 if (!cpuidle_state_is_coupled(drv, entered_state))
	local_irq_enable();

 [ ... ]

If the 'index' is referring to a coupled idle state but the
'entered_state' is *not* coupled, then the interrupts are enabled
again. All CPUs blocked on the sync barrier may busy loop longer
if the CPU has interrupts to handle before decrementing the
ready-count. That's consuming more energy than saving.

Fixes: 0b89e9aa2856 (cpuidle: delay enabling interrupts until all coupled CPUs leave idle)
Signed-off-by: Daniel Lezcano &lt;daniel.lezcano@linaro.org&gt;
Cc: 3.15+ &lt;stable@vger.kernel.org&gt; # 3.15+
[ rjw: Subject &amp; changelog ]
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=e7387da52028b072489c45efeb7a916c0205ebd2'>Diffstat</a> (limited to 'Documentation/misc-devices')</div><table summary='diffstat' class='diffstat'>