ieee802154/nl-mac.c: make some MLME operations optional

Check for NULL before calling the following operations from "struct
ieee802154_mlme_ops": assoc_req, assoc_resp, disassoc_req, start_req,
and scan_req.

This fixes a current oops where those functions are called but not
implemented. It also updates the documentation to clarify that they
are now optional by design. If a call to an unimplemented function
is attempted, the kernel returns EOPNOTSUPP via netlink.

The following operations are still required: get_phy, get_pan_id,
get_short_addr, and get_dsn.

Note that the places where this patch changes the initialization
of "ret" should not affect the rest of the code since "ret" was
always set (again) before returning its value.

Signed-off-by: Werner Almesberger <werner@almesberger.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 20 insertions, 5 deletions

diff --git a/net/ieee802154/nl-mac.c b/net/ieee802154/nl-mac.c
index 96bb08a..b0bdd8c 100644
--- a/net/ieee802154/nl-mac.c
+++ b/net/ieee802154/nl-mac.c
@@ -315,7 +315,7 @@ static int ieee802154_associate_req(struct sk_buff *skb,
 	struct net_device *dev;
 	struct ieee802154_addr addr;
 	u8 page;
-	int ret = -EINVAL;
+	int ret = -EOPNOTSUPP;
 
 	if (!info->attrs[IEEE802154_ATTR_CHANNEL] ||
 	    !info->attrs[IEEE802154_ATTR_COORD_PAN_ID] ||
@@ -327,6 +327,8 @@ static int ieee802154_associate_req(struct sk_buff *skb,
 	dev = ieee802154_nl_get_dev(info);
 	if (!dev)
 		return -ENODEV;
+	if (!ieee802154_mlme_ops(dev)->assoc_req)
+		goto out;
 
 	if (info->attrs[IEEE802154_ATTR_COORD_HW_ADDR]) {
 		addr.addr_type = IEEE802154_ADDR_LONG;
@@ -350,6 +352,7 @@ static int ieee802154_associate_req(struct sk_buff *skb,
 			page,
 			nla_get_u8(info->attrs[IEEE802154_ATTR_CAPABILITY]));
 
+out:
 	dev_put(dev);
 	return ret;
 }
@@ -359,7 +362,7 @@ static int ieee802154_associate_resp(struct sk_buff *skb,
 {
 	struct net_device *dev;
 	struct ieee802154_addr addr;
-	int ret = -EINVAL;
+	int ret = -EOPNOTSUPP;
 
 	if (!info->attrs[IEEE802154_ATTR_STATUS] ||
 	    !info->attrs[IEEE802154_ATTR_DEST_HW_ADDR] ||
@@ -369,6 +372,8 @@ static int ieee802154_associate_resp(struct sk_buff *skb,
 	dev = ieee802154_nl_get_dev(info);
 	if (!dev)
 		return -ENODEV;
+	if (!ieee802154_mlme_ops(dev)->assoc_resp)
+		goto out;
 
 	addr.addr_type = IEEE802154_ADDR_LONG;
 	nla_memcpy(addr.hwaddr, info->attrs[IEEE802154_ATTR_DEST_HW_ADDR],
@@ -380,6 +385,7 @@ static int ieee802154_associate_resp(struct sk_buff *skb,
 		nla_get_u16(info->attrs[IEEE802154_ATTR_DEST_SHORT_ADDR]),
 		nla_get_u8(info->attrs[IEEE802154_ATTR_STATUS]));
 
+out:
 	dev_put(dev);
 	return ret;
 }
@@ -389,7 +395,7 @@ static int ieee802154_disassociate_req(struct sk_buff *skb,
 {
 	struct net_device *dev;
 	struct ieee802154_addr addr;
-	int ret = -EINVAL;
+	int ret = -EOPNOTSUPP;
 
 	if ((!info->attrs[IEEE802154_ATTR_DEST_HW_ADDR] &&
 		!info->attrs[IEEE802154_ATTR_DEST_SHORT_ADDR]) ||
@@ -399,6 +405,8 @@ static int ieee802154_disassociate_req(struct sk_buff *skb,
 	dev = ieee802154_nl_get_dev(info);
 	if (!dev)
 		return -ENODEV;
+	if (!ieee802154_mlme_ops(dev)->disassoc_req)
+		goto out;
 
 	if (info->attrs[IEEE802154_ATTR_DEST_HW_ADDR]) {
 		addr.addr_type = IEEE802154_ADDR_LONG;
@@ -415,6 +423,7 @@ static int ieee802154_disassociate_req(struct sk_buff *skb,
 	ret = ieee802154_mlme_ops(dev)->disassoc_req(dev, &addr,
 			nla_get_u8(info->attrs[IEEE802154_ATTR_REASON]));
 
+out:
 	dev_put(dev);
 	return ret;
 }
@@ -432,7 +441,7 @@ static int ieee802154_start_req(struct sk_buff *skb, struct genl_info *info)
 	u8 channel, bcn_ord, sf_ord;
 	u8 page;
 	int pan_coord, blx, coord_realign;
-	int ret;
+	int ret = -EOPNOTSUPP;
 
 	if (!info->attrs[IEEE802154_ATTR_COORD_PAN_ID] ||
 	    !info->attrs[IEEE802154_ATTR_COORD_SHORT_ADDR] ||
@@ -448,6 +457,8 @@ static int ieee802154_start_req(struct sk_buff *skb, struct genl_info *info)
 	dev = ieee802154_nl_get_dev(info);
 	if (!dev)
 		return -ENODEV;
+	if (!ieee802154_mlme_ops(dev)->start_req)
+		goto out;
 
 	addr.addr_type = IEEE802154_ADDR_SHORT;
 	addr.short_addr = nla_get_u16(
@@ -476,6 +487,7 @@ static int ieee802154_start_req(struct sk_buff *skb, struct genl_info *info)
 	ret = ieee802154_mlme_ops(dev)->start_req(dev, &addr, channel, page,
 		bcn_ord, sf_ord, pan_coord, blx, coord_realign);
 
+out:
 	dev_put(dev);
 	return ret;
 }
@@ -483,7 +495,7 @@ static int ieee802154_start_req(struct sk_buff *skb, struct genl_info *info)
 static int ieee802154_scan_req(struct sk_buff *skb, struct genl_info *info)
 {
 	struct net_device *dev;
-	int ret;
+	int ret = -EOPNOTSUPP;
 	u8 type;
 	u32 channels;
 	u8 duration;
@@ -497,6 +509,8 @@ static int ieee802154_scan_req(struct sk_buff *skb, struct genl_info *info)
 	dev = ieee802154_nl_get_dev(info);
 	if (!dev)
 		return -ENODEV;
+	if (!ieee802154_mlme_ops(dev)->scan_req)
+		goto out;
 
 	type = nla_get_u8(info->attrs[IEEE802154_ATTR_SCAN_TYPE]);
 	channels = nla_get_u32(info->attrs[IEEE802154_ATTR_CHANNELS]);
@@ -511,6 +525,7 @@ static int ieee802154_scan_req(struct sk_buff *skb, struct genl_info *info)
 	ret = ieee802154_mlme_ops(dev)->scan_req(dev, type, channels, page,
 			duration);
 
+out:
 	dev_put(dev);
 	return ret;
 }