netlink: make nla_nest_start() add NLA_F_NESTED flag

Even if the NLA_F_NESTED flag was introduced more than 11 years ago, most
netlink based interfaces (including recently added ones) are still not
setting it in kernel generated messages. Without the flag, message parsers
not aware of attribute semantics (e.g. wireshark dissector or libmnl's
mnl_nlmsg_fprintf()) cannot recognize nested attributes and won't display
the structure of their contents.

Unfortunately we cannot just add the flag everywhere as there may be
userspace applications which check nlattr::nla_type directly rather than
through a helper masking out the flags. Therefore the patch renames
nla_nest_start() to nla_nest_start_noflag() and introduces nla_nest_start()
as a wrapper adding NLA_F_NESTED. The calls which add NLA_F_NESTED manually
are rewritten to use nla_nest_start().

Except for changes in include/net/netlink.h, the patch was generated using
this semantic patch:

@@ expression E1, E2; @@
-nla_nest_start(E1, E2)
+nla_nest_start_noflag(E1, E2)

@@ expression E1, E2; @@
-nla_nest_start_noflag(E1, E2 | NLA_F_NESTED)
+nla_nest_start(E1, E2)

Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 21 insertions, 19 deletions

diff --git a/net/dcb/dcbnl.c b/net/dcb/dcbnl.c
index a556cd708885..3fd3aa7348bd 100644
--- a/net/dcb/dcbnl.c
+++ b/net/dcb/dcbnl.c
@@ -246,7 +246,7 @@ static int dcbnl_getpfccfg(struct net_device *netdev, struct nlmsghdr *nlh,
 	if (ret)
 		return ret;
 
-	nest = nla_nest_start(skb, DCB_ATTR_PFC_CFG);
+	nest = nla_nest_start_noflag(skb, DCB_ATTR_PFC_CFG);
 	if (!nest)
 		return -EMSGSIZE;
 
@@ -304,7 +304,7 @@ static int dcbnl_getcap(struct net_device *netdev, struct nlmsghdr *nlh,
 	if (ret)
 		return ret;
 
-	nest = nla_nest_start(skb, DCB_ATTR_CAP);
+	nest = nla_nest_start_noflag(skb, DCB_ATTR_CAP);
 	if (!nest)
 		return -EMSGSIZE;
 
@@ -348,7 +348,7 @@ static int dcbnl_getnumtcs(struct net_device *netdev, struct nlmsghdr *nlh,
 	if (ret)
 		return ret;
 
-	nest = nla_nest_start(skb, DCB_ATTR_NUMTCS);
+	nest = nla_nest_start_noflag(skb, DCB_ATTR_NUMTCS);
 	if (!nest)
 		return -EMSGSIZE;
 
@@ -479,7 +479,7 @@ static int dcbnl_getapp(struct net_device *netdev, struct nlmsghdr *nlh,
 		up = dcb_getapp(netdev, &app);
 	}
 
-	app_nest = nla_nest_start(skb, DCB_ATTR_APP);
+	app_nest = nla_nest_start_noflag(skb, DCB_ATTR_APP);
 	if (!app_nest)
 		return -EMSGSIZE;
 
@@ -578,7 +578,7 @@ static int __dcbnl_pg_getcfg(struct net_device *netdev, struct nlmsghdr *nlh,
 	if (ret)
 		return ret;
 
-	pg_nest = nla_nest_start(skb, DCB_ATTR_PG_CFG);
+	pg_nest = nla_nest_start_noflag(skb, DCB_ATTR_PG_CFG);
 	if (!pg_nest)
 		return -EMSGSIZE;
 
@@ -598,7 +598,7 @@ static int __dcbnl_pg_getcfg(struct net_device *netdev, struct nlmsghdr *nlh,
 		if (ret)
 			goto err_pg;
 
-		param_nest = nla_nest_start(skb, i);
+		param_nest = nla_nest_start_noflag(skb, i);
 		if (!param_nest)
 			goto err_pg;
 
@@ -889,7 +889,7 @@ static int dcbnl_bcn_getcfg(struct net_device *netdev, struct nlmsghdr *nlh,
 	if (ret)
 		return ret;
 
-	bcn_nest = nla_nest_start(skb, DCB_ATTR_BCN);
+	bcn_nest = nla_nest_start_noflag(skb, DCB_ATTR_BCN);
 	if (!bcn_nest)
 		return -EMSGSIZE;
 
@@ -1002,7 +1002,7 @@ static int dcbnl_build_peer_app(struct net_device *netdev, struct sk_buff* skb,
 		 */
 		err = -EMSGSIZE;
 
-		app = nla_nest_start(skb, app_nested_type);
+		app = nla_nest_start_noflag(skb, app_nested_type);
 		if (!app)
 			goto nla_put_failure;
 
@@ -1036,7 +1036,7 @@ static int dcbnl_ieee_fill(struct sk_buff *skb, struct net_device *netdev)
 	if (nla_put_string(skb, DCB_ATTR_IFNAME, netdev->name))
 		return -EMSGSIZE;
 
-	ieee = nla_nest_start(skb, DCB_ATTR_IEEE);
+	ieee = nla_nest_start_noflag(skb, DCB_ATTR_IEEE);
 	if (!ieee)
 		return -EMSGSIZE;
 
@@ -1106,7 +1106,7 @@ static int dcbnl_ieee_fill(struct sk_buff *skb, struct net_device *netdev)
 			return -EMSGSIZE;
 	}
 
-	app = nla_nest_start(skb, DCB_ATTR_IEEE_APP_TABLE);
+	app = nla_nest_start_noflag(skb, DCB_ATTR_IEEE_APP_TABLE);
 	if (!app)
 		return -EMSGSIZE;
 
@@ -1174,13 +1174,13 @@ static int dcbnl_cee_pg_fill(struct sk_buff *skb, struct net_device *dev,
 	u8 pgid, up_map, prio, tc_pct;
 	const struct dcbnl_rtnl_ops *ops = dev->dcbnl_ops;
 	int i = dir ? DCB_ATTR_CEE_TX_PG : DCB_ATTR_CEE_RX_PG;
-	struct nlattr *pg = nla_nest_start(skb, i);
+	struct nlattr *pg = nla_nest_start_noflag(skb, i);
 
 	if (!pg)
 		return -EMSGSIZE;
 
 	for (i = DCB_PG_ATTR_TC_0; i <= DCB_PG_ATTR_TC_7; i++) {
-		struct nlattr *tc_nest = nla_nest_start(skb, i);
+		struct nlattr *tc_nest = nla_nest_start_noflag(skb, i);
 
 		if (!tc_nest)
 			return -EMSGSIZE;
@@ -1231,7 +1231,7 @@ static int dcbnl_cee_fill(struct sk_buff *skb, struct net_device *netdev)
 
 	if (nla_put_string(skb, DCB_ATTR_IFNAME, netdev->name))
 		goto nla_put_failure;
-	cee = nla_nest_start(skb, DCB_ATTR_CEE);
+	cee = nla_nest_start_noflag(skb, DCB_ATTR_CEE);
 	if (!cee)
 		goto nla_put_failure;
 
@@ -1250,7 +1250,8 @@ static int dcbnl_cee_fill(struct sk_buff *skb, struct net_device *netdev)
 
 	/* local pfc */
 	if (ops->getpfccfg) {
-		struct nlattr *pfc_nest = nla_nest_start(skb, DCB_ATTR_CEE_PFC);
+		struct nlattr *pfc_nest = nla_nest_start_noflag(skb,
+								DCB_ATTR_CEE_PFC);
 
 		if (!pfc_nest)
 			goto nla_put_failure;
@@ -1265,14 +1266,14 @@ static int dcbnl_cee_fill(struct sk_buff *skb, struct net_device *netdev)
 
 	/* local app */
 	spin_lock_bh(&dcb_lock);
-	app = nla_nest_start(skb, DCB_ATTR_CEE_APP_TABLE);
+	app = nla_nest_start_noflag(skb, DCB_ATTR_CEE_APP_TABLE);
 	if (!app)
 		goto dcb_unlock;
 
 	list_for_each_entry(itr, &dcb_app_list, list) {
 		if (itr->ifindex == netdev->ifindex) {
-			struct nlattr *app_nest = nla_nest_start(skb,
-								 DCB_ATTR_APP);
+			struct nlattr *app_nest = nla_nest_start_noflag(skb,
+									DCB_ATTR_APP);
 			if (!app_nest)
 				goto dcb_unlock;
 
@@ -1305,7 +1306,8 @@ static int dcbnl_cee_fill(struct sk_buff *skb, struct net_device *netdev)
 
 	/* features flags */
 	if (ops->getfeatcfg) {
-		struct nlattr *feat = nla_nest_start(skb, DCB_ATTR_CEE_FEAT);
+		struct nlattr *feat = nla_nest_start_noflag(skb,
+							    DCB_ATTR_CEE_FEAT);
 		if (!feat)
 			goto nla_put_failure;
 
@@ -1607,7 +1609,7 @@ static int dcbnl_getfeatcfg(struct net_device *netdev, struct nlmsghdr *nlh,
 	if (ret)
 		return ret;
 
-	nest = nla_nest_start(skb, DCB_ATTR_FEATCFG);
+	nest = nla_nest_start_noflag(skb, DCB_ATTR_FEATCFG);
 	if (!nest)
 		return -EMSGSIZE;