Re: [PATCH v2] mac80211: Fix the generation of PREQs in proactive RANN mechanism of HWMP

["John W. Linville" <linville@tuxdriver.com>]

  CC      net/mac80211/mesh_hwmp.o
net/mac80211/mesh_hwmp.c: In function ‘hwmp_preq_frame_process’:
net/mac80211/mesh_hwmp.c:597:7: warning: assignment discards qualifiers from pointer target type
net/mac80211/mesh_hwmp.c: In function ‘mesh_path_start_discovery’:
net/mac80211/mesh_hwmp.c:985:6: warning: assignment discards qualifiers from pointer target type
net/mac80211/mesh_hwmp.c: In function ‘hwmp_preq_frame_process’:
net/mac80211/mesh_hwmp.c:516:20: warning: ‘mpath’ may be used uninitialized in this function


On Wed, Feb 22, 2012 at 08:26:24AM +0800, Chun-Yeow Yeoh wrote:
> According to Section Y.7.4 Actions on receipt of proactive RANN, an individually
> addressed PREQ should be generated towards the neighbor peer mesh STA indicated
> in the RANN Sender Address field in the forwarding information.
> 
> Signed-off-by: Chun-Yeow Yeoh <yeohchunyeow@gmail.com>
> ---
>  net/mac80211/mesh.h      |    4 ++++
>  net/mac80211/mesh_hwmp.c |   24 +++++++++++++++++++-----
>  2 files changed, 23 insertions(+), 5 deletions(-)
> 
> diff --git a/net/mac80211/mesh.h b/net/mac80211/mesh.h
> index bd14bd2..4b0a9e8 100644
> --- a/net/mac80211/mesh.h
> +++ b/net/mac80211/mesh.h
> @@ -86,6 +86,8 @@ enum mesh_deferred_task_flags {
>   * @state_lock: mesh path state lock used to protect changes to the
>   * mpath itself.  No need to take this lock when adding or removing
>   * an mpath to a hash bucket on a path table.
> + * @rann_snd_addr: the RANN sender address
> + * @is_root: the destination station of this path is a root node
>   * @is_gate: the destination station of this path is a mesh gate
>   *
>   *
> @@ -110,6 +112,8 @@ struct mesh_path {
>  	u8 discovery_retries;
>  	enum mesh_path_flags flags;
>  	spinlock_t state_lock;
> +	u8 rann_snd_addr[ETH_ALEN];
> +	bool is_root;
>  	bool is_gate;
>  };
> 
> diff --git a/net/mac80211/mesh_hwmp.c b/net/mac80211/mesh_hwmp.c
> index cae4071..e24f5a1 100644
> --- a/net/mac80211/mesh_hwmp.c
> +++ b/net/mac80211/mesh_hwmp.c
> @@ -513,7 +513,7 @@ static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
>  {
>  	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
>  	struct mesh_path *mpath;
> -	u8 *target_addr, *orig_addr;
> +	u8 *target_addr, *orig_addr, *da;
>  	u8 target_flags, ttl;
>  	u32 orig_sn, target_sn, lifetime;
>  	bool reply = false;
> @@ -590,9 +590,13 @@ static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
>  		flags = PREQ_IE_FLAGS(preq_elem);
>  		preq_id = PREQ_IE_PREQ_ID(preq_elem);
>  		hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
> +		if (mpath && mpath->is_root)
> +			da = mpath->rann_snd_addr;
> +		else
> +			da = broadcast_addr;
>  		mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
>  				cpu_to_le32(orig_sn), target_flags, target_addr,
> -				cpu_to_le32(target_sn), broadcast_addr,
> +				cpu_to_le32(target_sn), da,
>  				hopcount, ttl, cpu_to_le32(lifetime),
>  				cpu_to_le32(metric), cpu_to_le32(preq_id),
>  				sdata);
> @@ -741,8 +745,8 @@ static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
>  	if (memcmp(orig_addr, sdata->vif.addr, ETH_ALEN) == 0)
>  		return;
> 
> -	mhwmp_dbg("received RANN from %pM (is_gate=%d)", orig_addr,
> -			root_is_gate);
> +	mhwmp_dbg("received RANN from %pM via neighbour %pM (is_gate=%d)",
> +			orig_addr, mgmt->sa, root_is_gate);
> 
>  	rcu_read_lock();
>  	mpath = mesh_path_lookup(orig_addr, sdata);
> @@ -773,6 +777,11 @@ static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
>  				       0, sdata);
>  		mpath->sn = orig_sn;
>  	}
> +
> +	/* Using individually addressed PREQ for root node */
> +	memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
> +	mpath->is_root = true;
> +
>  	if (root_is_gate)
>  		mesh_path_add_gate(mpath);
> 
> @@ -908,6 +917,7 @@ void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
>  	struct mesh_preq_queue *preq_node;
>  	struct mesh_path *mpath;
>  	u8 ttl, target_flags;
> +	u8 *da;
>  	u32 lifetime;
> 
>  	spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
> @@ -970,9 +980,13 @@ void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
>  		target_flags = MP_F_RF;
> 
>  	spin_unlock_bh(&mpath->state_lock);
> +	if (!mpath->is_root)
> +		da = broadcast_addr;
> +	else
> +		da = mpath->rann_snd_addr;
>  	mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr,
>  			cpu_to_le32(ifmsh->sn), target_flags, mpath->dst,
> -			cpu_to_le32(mpath->sn), broadcast_addr, 0,
> +			cpu_to_le32(mpath->sn), da, 0,
>  			ttl, cpu_to_le32(lifetime), 0,
>  			cpu_to_le32(ifmsh->preq_id++), sdata);
>  	mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
> --
> 1.7.0.4
> 
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-- 
John W. Linville		Someday the world will need a hero, and you
linville@tuxdriver.com			might be all we have.  Be ready.