[PATCH v4 0/2] cfg80211: Add export of mesh proxy path table

[PATCH v4 0/2] cfg80211: Add export of mesh proxy path table

[Henning Rogge]

The following patch series adds and implements two new cfg80211_ops that
allow to query the content of the mac80211s mesh proxy path table via
netlink.

v2 changes:
* split the original patch into separate cfg80211 and mac80211 part

v3 change:
* change of commit messages, added signoff

v4 change:
* another change of commit messages

Henning Rogge (2):
  cfg80211: add ops to query mesh proxy path table
  mac80211: implement cfg80211_ops to query mesh proxy path table

 include/net/cfg80211.h       |  7 ++++
 include/uapi/linux/nl80211.h |  6 +++
 net/mac80211/cfg.c           | 53 ++++++++++++++++++++++++
 net/mac80211/mesh.h          |  3 ++
 net/mac80211/mesh_pathtbl.c  | 31 ++++++++++++++
 net/wireless/nl80211.c       | 99 ++++++++++++++++++++++++++++++++++++++++++++
 net/wireless/rdev-ops.h      | 27 +++++++++++-
 net/wireless/trace.h         | 45 ++++++++++++++++++++
 8 files changed, 270 insertions(+), 1 deletion(-)

-- 
1.9.1

[PATCH v4 1/2] cfg80211: add ops to query mesh proxy path table

[Henning Rogge]

Add two new cfg80211 operations for querying a table with proxied mesh
paths.

Signed-off-by: Henning Rogge <henning.rogge@fkie.fraunhofer.de>
---
 include/net/cfg80211.h       |  7 ++++
 include/uapi/linux/nl80211.h |  6 +++
 net/wireless/nl80211.c       | 99 ++++++++++++++++++++++++++++++++++++++++++++
 net/wireless/rdev-ops.h      | 27 +++++++++++-
 net/wireless/trace.h         | 45 ++++++++++++++++++++
 5 files changed, 183 insertions(+), 1 deletion(-)

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index ab21299..1d1467f 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -2141,6 +2141,8 @@ struct cfg80211_qos_map {
  * @change_mpath: change a given mesh path
  * @get_mpath: get a mesh path for the given parameters
  * @dump_mpath: dump mesh path callback -- resume dump at index @idx
+ * @get_mpp: get a mesh proxy path for the given parameters
+ * @dump_mpp: dump mesh proxy path callback -- resume dump at index @idx
  * @join_mesh: join the mesh network with the specified parameters
  *	(invoked with the wireless_dev mutex held)
  * @leave_mesh: leave the current mesh network
@@ -2380,6 +2382,11 @@ struct cfg80211_ops {
 	int	(*dump_mpath)(struct wiphy *wiphy, struct net_device *dev,
 			      int idx, u8 *dst, u8 *next_hop,
 			      struct mpath_info *pinfo);
+	int	(*get_mpp)(struct wiphy *wiphy, struct net_device *dev,
+			   u8 *dst, u8 *mpp, struct mpath_info *pinfo);
+	int	(*dump_mpp)(struct wiphy *wiphy, struct net_device *dev,
+			    int idx, u8 *dst, u8 *mpp,
+			    struct mpath_info *pinfo);
 	int	(*get_mesh_config)(struct wiphy *wiphy,
 				struct net_device *dev,
 				struct mesh_config *conf);
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index d097568..b5c5052 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -722,6 +722,10 @@
  *	QoS mapping is relevant for IP packets, it is only valid during an
  *	association. This is cleared on disassociation and AP restart.
  *
+ * @NL80211_CMD_GET_MPP: Get mesh path attributes for mesh proxy path to
+ *	destination %NL80211_ATTR_MAC on the interface identified by
+ *	%NL80211_ATTR_IFINDEX.
+ *
  * @NL80211_CMD_MAX: highest used command number
  * @__NL80211_CMD_AFTER_LAST: internal use
  */
@@ -893,6 +897,8 @@ enum nl80211_commands {
 
 	NL80211_CMD_SET_QOS_MAP,
 
+	NL80211_CMD_GET_MPP,
+
 	/* add new commands above here */
 
 	/* used to define NL80211_CMD_MAX below */
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 3011401..cbaf722 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -4581,6 +4581,96 @@ static int nl80211_del_mpath(struct sk_buff *skb, struct genl_info *info)
 	return rdev_del_mpath(rdev, dev, dst);
 }
 
+static int nl80211_get_mpp(struct sk_buff *skb, struct genl_info *info)
+{
+	struct cfg80211_registered_device *rdev = info->user_ptr[0];
+	int err;
+	struct net_device *dev = info->user_ptr[1];
+	struct mpath_info pinfo;
+	struct sk_buff *msg;
+	u8 *dst = NULL;
+	u8 mpp[ETH_ALEN];
+
+	memset(&pinfo, 0, sizeof(pinfo));
+
+	if (!info->attrs[NL80211_ATTR_MAC])
+		return -EINVAL;
+
+	dst = nla_data(info->attrs[NL80211_ATTR_MAC]);
+
+	if (!rdev->ops->get_mpp)
+		return -EOPNOTSUPP;
+
+	if (dev->ieee80211_ptr->iftype != NL80211_IFTYPE_MESH_POINT)
+		return -EOPNOTSUPP;
+
+	err = rdev_get_mpp(rdev, dev, dst, mpp, &pinfo);
+	if (err)
+		return err;
+
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	if (nl80211_send_mpath(msg, info->snd_portid, info->snd_seq, 0,
+			       dev, dst, mpp, &pinfo) < 0) {
+		nlmsg_free(msg);
+		return -ENOBUFS;
+	}
+
+	return genlmsg_reply(msg, info);
+}
+
+static int nl80211_dump_mpp(struct sk_buff *skb,
+			    struct netlink_callback *cb)
+{
+	struct mpath_info pinfo;
+	struct cfg80211_registered_device *rdev;
+	struct wireless_dev *wdev;
+	u8 dst[ETH_ALEN];
+	u8 mpp[ETH_ALEN];
+	int path_idx = cb->args[2];
+	int err;
+
+	err = nl80211_prepare_wdev_dump(skb, cb, &rdev, &wdev);
+	if (err)
+		return err;
+
+	if (!rdev->ops->dump_mpp) {
+		err = -EOPNOTSUPP;
+		goto out_err;
+	}
+
+	if (wdev->iftype != NL80211_IFTYPE_MESH_POINT) {
+		err = -EOPNOTSUPP;
+		goto out_err;
+	}
+
+	while (1) {
+		err = rdev_dump_mpp(rdev, wdev->netdev, path_idx, dst,
+				    mpp, &pinfo);
+		if (err == -ENOENT)
+			break;
+		if (err)
+			goto out_err;
+
+		if (nl80211_send_mpath(skb, NETLINK_CB(cb->skb).portid,
+				       cb->nlh->nlmsg_seq, NLM_F_MULTI,
+				       wdev->netdev, dst, mpp,
+				       &pinfo) < 0)
+			goto out;
+
+		path_idx++;
+	}
+
+ out:
+	cb->args[2] = path_idx;
+	err = skb->len;
+ out_err:
+	nl80211_finish_wdev_dump(rdev);
+	return err;
+}
+
 static int nl80211_set_bss(struct sk_buff *skb, struct genl_info *info)
 {
 	struct cfg80211_registered_device *rdev = info->user_ptr[0];
@@ -9611,6 +9701,15 @@ static const struct genl_ops nl80211_ops[] = {
 				  NL80211_FLAG_NEED_RTNL,
 	},
 	{
+		.cmd = NL80211_CMD_GET_MPP,
+		.doit = nl80211_get_mpp,
+		.dumpit = nl80211_dump_mpp,
+		.policy = nl80211_policy,
+		.flags = GENL_ADMIN_PERM,
+		.internal_flags = NL80211_FLAG_NEED_NETDEV_UP |
+				  NL80211_FLAG_NEED_RTNL,
+	},
+	{
 		.cmd = NL80211_CMD_SET_MPATH,
 		.doit = nl80211_set_mpath,
 		.policy = nl80211_policy,
diff --git a/net/wireless/rdev-ops.h b/net/wireless/rdev-ops.h
index 56c2240..e5560d5 100644
--- a/net/wireless/rdev-ops.h
+++ b/net/wireless/rdev-ops.h
@@ -263,6 +263,18 @@ static inline int rdev_get_mpath(struct cfg80211_registered_device *rdev,
 
 }
 
+static inline int rdev_get_mpp(struct cfg80211_registered_device *rdev,
+			       struct net_device *dev, u8 *dst, u8 *mpp,
+			       struct mpath_info *pinfo)
+{
+	int ret;
+
+	trace_rdev_get_mpp(&rdev->wiphy, dev, dst, mpp);
+	ret = rdev->ops->get_mpp(&rdev->wiphy, dev, dst, mpp, pinfo);
+	trace_rdev_return_int_mpath_info(&rdev->wiphy, ret, pinfo);
+	return ret;
+}
+
 static inline int rdev_dump_mpath(struct cfg80211_registered_device *rdev,
 				  struct net_device *dev, int idx, u8 *dst,
 				  u8 *next_hop, struct mpath_info *pinfo)
@@ -271,7 +283,20 @@ static inline int rdev_dump_mpath(struct cfg80211_registered_device *rdev,
 	int ret;
 	trace_rdev_dump_mpath(&rdev->wiphy, dev, idx, dst, next_hop);
 	ret = rdev->ops->dump_mpath(&rdev->wiphy, dev, idx, dst, next_hop,
-				     pinfo);
+				    pinfo);
+	trace_rdev_return_int_mpath_info(&rdev->wiphy, ret, pinfo);
+	return ret;
+}
+
+static inline int rdev_dump_mpp(struct cfg80211_registered_device *rdev,
+				struct net_device *dev, int idx, u8 *dst,
+				u8 *mpp, struct mpath_info *pinfo)
+
+{
+	int ret;
+
+	trace_rdev_dump_mpp(&rdev->wiphy, dev, idx, dst, mpp);
+	ret = rdev->ops->dump_mpp(&rdev->wiphy, dev, idx, dst, mpp, pinfo);
 	trace_rdev_return_int_mpath_info(&rdev->wiphy, ret, pinfo);
 	return ret;
 }
diff --git a/net/wireless/trace.h b/net/wireless/trace.h
index 0c524cd..57ab727 100644
--- a/net/wireless/trace.h
+++ b/net/wireless/trace.h
@@ -801,6 +801,51 @@ TRACE_EVENT(rdev_dump_mpath,
 		  MAC_PR_ARG(next_hop))
 );
 
+TRACE_EVENT(rdev_get_mpp,
+	TP_PROTO(struct wiphy *wiphy, struct net_device *netdev,
+		 u8 *dst, u8 *mpp),
+	TP_ARGS(wiphy, netdev, dst, mpp),
+	TP_STRUCT__entry(
+		WIPHY_ENTRY
+		NETDEV_ENTRY
+		MAC_ENTRY(dst)
+		MAC_ENTRY(mpp)
+	),
+	TP_fast_assign(
+		WIPHY_ASSIGN;
+		NETDEV_ASSIGN;
+		MAC_ASSIGN(dst, dst);
+		MAC_ASSIGN(mpp, mpp);
+	),
+	TP_printk(WIPHY_PR_FMT ", " NETDEV_PR_FMT ", destination: " MAC_PR_FMT
+		  ", mpp: " MAC_PR_FMT, WIPHY_PR_ARG, NETDEV_PR_ARG,
+		  MAC_PR_ARG(dst), MAC_PR_ARG(mpp))
+);
+
+TRACE_EVENT(rdev_dump_mpp,
+	TP_PROTO(struct wiphy *wiphy, struct net_device *netdev, int idx,
+		 u8 *dst, u8 *mpp),
+	TP_ARGS(wiphy, netdev, idx, mpp, dst),
+	TP_STRUCT__entry(
+		WIPHY_ENTRY
+		NETDEV_ENTRY
+		MAC_ENTRY(dst)
+		MAC_ENTRY(mpp)
+		__field(int, idx)
+	),
+	TP_fast_assign(
+		WIPHY_ASSIGN;
+		NETDEV_ASSIGN;
+		MAC_ASSIGN(dst, dst);
+		MAC_ASSIGN(mpp, mpp);
+		__entry->idx = idx;
+	),
+	TP_printk(WIPHY_PR_FMT ", " NETDEV_PR_FMT ", index: %d, destination: "
+		  MAC_PR_FMT ", mpp: " MAC_PR_FMT,
+		  WIPHY_PR_ARG, NETDEV_PR_ARG, __entry->idx, MAC_PR_ARG(dst),
+		  MAC_PR_ARG(mpp))
+);
+
 TRACE_EVENT(rdev_return_int_mpath_info,
 	TP_PROTO(struct wiphy *wiphy, int ret, struct mpath_info *pinfo),
 	TP_ARGS(wiphy, ret, pinfo),
-- 
1.9.1

[PATCH v4 2/2] mac80211: implement cfg80211_ops to query mesh proxy path table

[Henning Rogge]

Implement get_mpp and dump_mpp cfg80211_ops to export the content of the
802.11s mesh proxy path table to userspace.

Signed-off-by: Henning Rogge <henning.rogge@fkie.fraunhofer.de>
---
 net/mac80211/cfg.c          | 53 +++++++++++++++++++++++++++++++++++++++++++++
 net/mac80211/mesh.h         |  3 +++
 net/mac80211/mesh_pathtbl.c | 31 ++++++++++++++++++++++++++
 3 files changed, 87 insertions(+)

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 4d8989b..2538a2f 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1504,6 +1504,57 @@ static int ieee80211_dump_mpath(struct wiphy *wiphy, struct net_device *dev,
 	return 0;
 }
 
+static void mpp_set_pinfo(struct mesh_path *mpath, u8 *mpp,
+			  struct mpath_info *pinfo)
+{
+	memset(pinfo, 0, sizeof(*pinfo));
+	memcpy(mpp, mpath->mpp, ETH_ALEN);
+
+	pinfo->generation = mpp_paths_generation;
+}
+
+static int ieee80211_get_mpp(struct wiphy *wiphy, struct net_device *dev,
+			     u8 *dst, u8 *mpp, struct mpath_info *pinfo)
+
+{
+	struct ieee80211_sub_if_data *sdata;
+	struct mesh_path *mpath;
+
+	sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+
+	rcu_read_lock();
+	mpath = mpp_path_lookup(sdata, dst);
+	if (!mpath) {
+		rcu_read_unlock();
+		return -ENOENT;
+	}
+	memcpy(dst, mpath->dst, ETH_ALEN);
+	mpp_set_pinfo(mpath, mpp, pinfo);
+	rcu_read_unlock();
+	return 0;
+}
+
+static int ieee80211_dump_mpp(struct wiphy *wiphy, struct net_device *dev,
+			      int idx, u8 *dst, u8 *mpp,
+			      struct mpath_info *pinfo)
+{
+	struct ieee80211_sub_if_data *sdata;
+	struct mesh_path *mpath;
+
+	sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+
+	rcu_read_lock();
+	mpath = mpp_path_lookup_by_idx(sdata, idx);
+	if (!mpath) {
+		rcu_read_unlock();
+		return -ENOENT;
+	}
+	memcpy(dst, mpath->dst, ETH_ALEN);
+	mpp_set_pinfo(mpath, mpp, pinfo);
+	rcu_read_unlock();
+	return 0;
+}
+
 static int ieee80211_get_mesh_config(struct wiphy *wiphy,
 				struct net_device *dev,
 				struct mesh_config *conf)
@@ -3500,6 +3551,8 @@ const struct cfg80211_ops mac80211_config_ops = {
 	.change_mpath = ieee80211_change_mpath,
 	.get_mpath = ieee80211_get_mpath,
 	.dump_mpath = ieee80211_dump_mpath,
+	.get_mpp = ieee80211_get_mpp,
+	.dump_mpp = ieee80211_dump_mpp,
 	.update_mesh_config = ieee80211_update_mesh_config,
 	.get_mesh_config = ieee80211_get_mesh_config,
 	.join_mesh = ieee80211_join_mesh,
diff --git a/net/mac80211/mesh.h b/net/mac80211/mesh.h
index f39a19f..50c8473 100644
--- a/net/mac80211/mesh.h
+++ b/net/mac80211/mesh.h
@@ -270,6 +270,8 @@ int mpp_path_add(struct ieee80211_sub_if_data *sdata,
 		 const u8 *dst, const u8 *mpp);
 struct mesh_path *
 mesh_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx);
+struct mesh_path *
+mpp_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx);
 void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop);
 void mesh_path_expire(struct ieee80211_sub_if_data *sdata);
 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
@@ -317,6 +319,7 @@ void mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata);
 
 bool mesh_action_is_path_sel(struct ieee80211_mgmt *mgmt);
 extern int mesh_paths_generation;
+extern int mpp_paths_generation;
 
 #ifdef CONFIG_MAC80211_MESH
 static inline
diff --git a/net/mac80211/mesh_pathtbl.c b/net/mac80211/mesh_pathtbl.c
index a6699dc..b890e22 100644
--- a/net/mac80211/mesh_pathtbl.c
+++ b/net/mac80211/mesh_pathtbl.c
@@ -44,6 +44,7 @@ static struct mesh_table __rcu *mesh_paths;
 static struct mesh_table __rcu *mpp_paths; /* Store paths for MPP&MAP */
 
 int mesh_paths_generation;
+int mpp_paths_generation;
 
 /* This lock will have the grow table function as writer and add / delete nodes
  * as readers. RCU provides sufficient protection only when reading the table
@@ -410,6 +411,33 @@ mesh_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx)
 }
 
 /**
+ * mpp_path_lookup_by_idx - look up a path in the proxy path table by its index
+ * @idx: index
+ * @sdata: local subif, or NULL for all entries
+ *
+ * Returns: pointer to the proxy path structure, or NULL if not found.
+ *
+ * Locking: must be called within a read rcu section.
+ */
+struct mesh_path *
+mpp_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx)
+{
+	struct mesh_table *tbl = rcu_dereference(mpp_paths);
+	struct mpath_node *node;
+	int i;
+	int j = 0;
+
+	for_each_mesh_entry(tbl, node, i) {
+		if (sdata && node->mpath->sdata != sdata)
+			continue;
+		if (j++ == idx)
+			return node->mpath;
+	}
+
+	return NULL;
+}
+
+/**
  * mesh_path_add_gate - add the given mpath to a mesh gate to our path table
  * @mpath: gate path to add to table
  */
@@ -691,6 +719,9 @@ int mpp_path_add(struct ieee80211_sub_if_data *sdata,
 
 	spin_unlock(&tbl->hashwlock[hash_idx]);
 	read_unlock_bh(&pathtbl_resize_lock);
+
+	mpp_paths_generation++;
+
 	if (grow) {
 		set_bit(MESH_WORK_GROW_MPP_TABLE,  &ifmsh->wrkq_flags);
 		ieee80211_queue_work(&local->hw, &sdata->work);
-- 
1.9.1

Re: [PATCH v4 2/2] mac80211: implement cfg80211_ops to query mesh proxy path table

[Johannes Berg]

On Fri, 2014-09-12 at 08:58 +0200, Henning Rogge wrote:
[...]

In general, this looks fine. However,

> @@ -691,6 +719,9 @@ int mpp_path_add(struct ieee80211_sub_if_data *sdata,
>  
>  	spin_unlock(&tbl->hashwlock[hash_idx]);
>  	read_unlock_bh(&pathtbl_resize_lock);
> +
> +	mpp_paths_generation++;

This doesn't seem to be concurrency safe?

Neither is the existing mesh_paths_generation++, I think, so maybe it's
not something we really need to worry about?

johannes

Re: [PATCH v4 2/2] mac80211: implement cfg80211_ops to query mesh proxy path table

[Henning Rogge]

On Thu, Oct 9, 2014 at 9:38 AM, Johannes Berg <johannes@sipsolutions.net> wrote:
> On Fri, 2014-09-12 at 08:58 +0200, Henning Rogge wrote:
> [...]
>
> In general, this looks fine. However,
>
>> @@ -691,6 +719,9 @@ int mpp_path_add(struct ieee80211_sub_if_data *sdata,
>>
>>       spin_unlock(&tbl->hashwlock[hash_idx]);
>>       read_unlock_bh(&pathtbl_resize_lock);
>> +
>> +     mpp_paths_generation++;
>
> This doesn't seem to be concurrency safe?
>
> Neither is the existing mesh_paths_generation++, I think, so maybe it's
> not something we really need to worry about?

Uhh... I must admit I am not completely sure... this is just my third
kernel patch, so I am still learning about all the arcane locking/RCU
systems of the kernel.

I think it should be reasonable safe. The variable is only increased
(never decreased) and is used as a "information version number" for
the dumps via netlink to the userspace. I think the current userspace
tools ignore the variable completely.

Henning Rogge

Re: [PATCH v4 2/2] mac80211: implement cfg80211_ops to query mesh proxy path table

[Johannes Berg]

On Thu, 2014-10-09 at 10:10 +0200, Henning Rogge wrote:

> I think it should be reasonable safe. The variable is only increased
> (never decreased) and is used as a "information version number" for
> the dumps via netlink to the userspace. I think the current userspace
> tools ignore the variable completely.

Fair enough. I'll apply it. If an update is lost, it's likely that
userspace saw a previous value anyway.

johannes

Re: [PATCH v4 0/2] cfg80211: Add export of mesh proxy path table

[Johannes Berg]

On Fri, 2014-09-12 at 08:58 +0200, Henning Rogge wrote:
> The following patch series adds and implements two new cfg80211_ops that
> allow to query the content of the mac80211s mesh proxy path table via
> netlink.

Both applied.

johannes