batman-adv: Make MCAST capability changes atomic
Bitwise OR/AND assignments in C aren't guaranteed to be atomic. One
OGM handler might undo the set/clear of a specific bit from another
handler run in between.
Fix this by using the atomic set_bit()/clear_bit()/test_bit() functions.
Fixes: 60432d756c
("batman-adv: Announce new capability via multicast TVLV")
Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>
This commit is contained in:
Родитель
ac4eebd484
Коммит
9c936e3f4c
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@ -19,6 +19,7 @@
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#include "main.h"
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#include <linux/atomic.h>
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#include <linux/bitops.h>
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#include <linux/byteorder/generic.h>
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#include <linux/errno.h>
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#include <linux/etherdevice.h>
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@ -697,29 +698,30 @@ static void batadv_mcast_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv,
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uint8_t mcast_flags = BATADV_NO_FLAGS;
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bool orig_initialized;
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orig_initialized = orig->capa_initialized & BATADV_ORIG_CAPA_HAS_MCAST;
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orig_initialized = test_bit(BATADV_ORIG_CAPA_HAS_MCAST,
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&orig->capa_initialized);
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/* If mcast support is turned on decrease the disabled mcast node
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* counter only if we had increased it for this node before. If this
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* is a completely new orig_node no need to decrease the counter.
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*/
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if (orig_mcast_enabled &&
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!(orig->capabilities & BATADV_ORIG_CAPA_HAS_MCAST)) {
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!test_bit(BATADV_ORIG_CAPA_HAS_MCAST, &orig->capabilities)) {
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if (orig_initialized)
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atomic_dec(&bat_priv->mcast.num_disabled);
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orig->capabilities |= BATADV_ORIG_CAPA_HAS_MCAST;
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set_bit(BATADV_ORIG_CAPA_HAS_MCAST, &orig->capabilities);
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/* If mcast support is being switched off or if this is an initial
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* OGM without mcast support then increase the disabled mcast
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* node counter.
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*/
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} else if (!orig_mcast_enabled &&
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(orig->capabilities & BATADV_ORIG_CAPA_HAS_MCAST ||
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(test_bit(BATADV_ORIG_CAPA_HAS_MCAST, &orig->capabilities) ||
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!orig_initialized)) {
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atomic_inc(&bat_priv->mcast.num_disabled);
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orig->capabilities &= ~BATADV_ORIG_CAPA_HAS_MCAST;
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clear_bit(BATADV_ORIG_CAPA_HAS_MCAST, &orig->capabilities);
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}
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orig->capa_initialized |= BATADV_ORIG_CAPA_HAS_MCAST;
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set_bit(BATADV_ORIG_CAPA_HAS_MCAST, &orig->capa_initialized);
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if (orig_mcast_enabled && tvlv_value &&
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(tvlv_value_len >= sizeof(mcast_flags)))
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@ -763,8 +765,8 @@ void batadv_mcast_purge_orig(struct batadv_orig_node *orig)
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{
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struct batadv_priv *bat_priv = orig->bat_priv;
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if (!(orig->capabilities & BATADV_ORIG_CAPA_HAS_MCAST) &&
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orig->capa_initialized & BATADV_ORIG_CAPA_HAS_MCAST)
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if (!test_bit(BATADV_ORIG_CAPA_HAS_MCAST, &orig->capabilities) &&
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test_bit(BATADV_ORIG_CAPA_HAS_MCAST, &orig->capa_initialized))
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atomic_dec(&bat_priv->mcast.num_disabled);
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batadv_mcast_want_unsnoop_update(bat_priv, orig, BATADV_NO_FLAGS);
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@ -316,7 +316,7 @@ enum batadv_orig_capabilities {
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BATADV_ORIG_CAPA_HAS_DAT,
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BATADV_ORIG_CAPA_HAS_NC,
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BATADV_ORIG_CAPA_HAS_TT,
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BATADV_ORIG_CAPA_HAS_MCAST = BIT(3),
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BATADV_ORIG_CAPA_HAS_MCAST,
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};
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/**
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