Commit 65d7d460 authored by Linus Lüssing's avatar Linus Lüssing Committed by Antonio Quartulli
Browse files

batman-adv: Make DAT 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: 17cf0ea4 ("batman-adv: tvlv - add distributed arp table 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 571a9637

net/batman-adv/distributed-arp-table.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/errno.h>

#include <linux/etherdevice.h>
@@ -453,7 +454,7 @@ static bool batadv_is_orig_node_eligible(struct batadv_dat_candidate *res, 
	int j;



	/* check if orig node candidate is running DAT */

	if (!(candidate->capabilities & BATADV_ORIG_CAPA_HAS_DAT))

	if (!test_bit(BATADV_ORIG_CAPA_HAS_DAT, &candidate->capabilities))

		goto out;



	/* Check if this node has already been selected... */
@@ -713,9 +714,9 @@ static void batadv_dat_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_DAT;

		clear_bit(BATADV_ORIG_CAPA_HAS_DAT, &orig->capabilities);

	else

		orig->capabilities |= BATADV_ORIG_CAPA_HAS_DAT;

		set_bit(BATADV_ORIG_CAPA_HAS_DAT, &orig->capabilities);

}



/**

net/batman-adv/types.h

+2 −2
Original line number Diff line number Diff line
@@ -273,7 +273,7 @@ struct batadv_orig_node { 
	struct hlist_node mcast_want_all_ipv4_node;

	struct hlist_node mcast_want_all_ipv6_node;

#endif

	uint8_t capabilities;

	unsigned long capabilities;

	uint8_t capa_initialized;

	atomic_t last_ttvn;

	unsigned char *tt_buff;
@@ -313,7 +313,7 @@ struct batadv_orig_node { 
 *  (= orig node announces a tvlv of type BATADV_TVLV_MCAST)

 */

enum batadv_orig_capabilities {

	BATADV_ORIG_CAPA_HAS_DAT = BIT(0),

	BATADV_ORIG_CAPA_HAS_DAT,

	BATADV_ORIG_CAPA_HAS_NC = BIT(1),

	BATADV_ORIG_CAPA_HAS_TT = BIT(2),

	BATADV_ORIG_CAPA_HAS_MCAST = BIT(3),

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