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Commit 4635469f authored by Linus Lüssing's avatar Linus Lüssing Committed by Antonio Quartulli
Browse files

batman-adv: Make NC 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: 3f4841ff ("batman-adv: tvlv - add network coding container")
Signed-off-by: default avatarLinus Lüssing <linus.luessing@c0d3.blue>
Signed-off-by: default avatarMarek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: default avatarAntonio Quartulli <antonio@meshcoding.com>
parent 65d7d460

net/batman-adv/network-coding.c

+4 −3
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
#include "main.h"



#include <linux/atomic.h>

#include <linux/bitops.h>

#include <linux/byteorder/generic.h>

#include <linux/compiler.h>

#include <linux/debugfs.h>
@@ -134,9 +135,9 @@ static void batadv_nc_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv, 
					  uint16_t tvlv_value_len)

{

	if (flags & BATADV_TVLV_HANDLER_OGM_CIFNOTFND)

		orig->capabilities &= ~BATADV_ORIG_CAPA_HAS_NC;

		clear_bit(BATADV_ORIG_CAPA_HAS_NC, &orig->capabilities);

	else

		orig->capabilities |= BATADV_ORIG_CAPA_HAS_NC;

		set_bit(BATADV_ORIG_CAPA_HAS_NC, &orig->capabilities);

}



/**
@@ -894,7 +895,7 @@ void batadv_nc_update_nc_node(struct batadv_priv *bat_priv, 
		goto out;



	/* check if orig node is network coding enabled */

	if (!(orig_node->capabilities & BATADV_ORIG_CAPA_HAS_NC))

	if (!test_bit(BATADV_ORIG_CAPA_HAS_NC, &orig_node->capabilities))

		goto out;



	/* accept ogms from 'good' neighbors and single hop neighbors */

net/batman-adv/types.h

+1 −1
Original line number Diff line number Diff line
@@ -314,7 +314,7 @@ struct batadv_orig_node { 
 */

enum batadv_orig_capabilities {

	BATADV_ORIG_CAPA_HAS_DAT,

	BATADV_ORIG_CAPA_HAS_NC = BIT(1),

	BATADV_ORIG_CAPA_HAS_NC,

	BATADV_ORIG_CAPA_HAS_TT = BIT(2),

	BATADV_ORIG_CAPA_HAS_MCAST = BIT(3),

};