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, 17 insertions, 16 deletions

diff --git a/net/openvswitch/flow_netlink.c b/net/openvswitch/flow_netlink.c
index 3563acd5f92e..2427b672107a 100644
--- a/net/openvswitch/flow_netlink.c
+++ b/net/openvswitch/flow_netlink.c
@@ -856,7 +856,7 @@ static int vxlan_opt_to_nlattr(struct sk_buff *skb,
 	const struct vxlan_metadata *opts = tun_opts;
 	struct nlattr *nla;
 
-	nla = nla_nest_start(skb, OVS_TUNNEL_KEY_ATTR_VXLAN_OPTS);
+	nla = nla_nest_start_noflag(skb, OVS_TUNNEL_KEY_ATTR_VXLAN_OPTS);
 	if (!nla)
 		return -EMSGSIZE;
 
@@ -948,7 +948,7 @@ static int ip_tun_to_nlattr(struct sk_buff *skb,
 	struct nlattr *nla;
 	int err;
 
-	nla = nla_nest_start(skb, OVS_KEY_ATTR_TUNNEL);
+	nla = nla_nest_start_noflag(skb, OVS_KEY_ATTR_TUNNEL);
 	if (!nla)
 		return -EMSGSIZE;
 
@@ -1957,7 +1957,7 @@ static int nsh_key_to_nlattr(const struct ovs_key_nsh *nsh, bool is_mask,
 {
 	struct nlattr *start;
 
-	start = nla_nest_start(skb, OVS_KEY_ATTR_NSH);
+	start = nla_nest_start_noflag(skb, OVS_KEY_ATTR_NSH);
 	if (!start)
 		return -EMSGSIZE;
 
@@ -2040,14 +2040,15 @@ static int __ovs_nla_put_key(const struct sw_flow_key *swkey,
 		if (swkey->eth.vlan.tci || eth_type_vlan(swkey->eth.type)) {
 			if (ovs_nla_put_vlan(skb, &output->eth.vlan, is_mask))
 				goto nla_put_failure;
-			encap = nla_nest_start(skb, OVS_KEY_ATTR_ENCAP);
+			encap = nla_nest_start_noflag(skb, OVS_KEY_ATTR_ENCAP);
 			if (!swkey->eth.vlan.tci)
 				goto unencap;
 
 			if (swkey->eth.cvlan.tci || eth_type_vlan(swkey->eth.type)) {
 				if (ovs_nla_put_vlan(skb, &output->eth.cvlan, is_mask))
 					goto nla_put_failure;
-				in_encap = nla_nest_start(skb, OVS_KEY_ATTR_ENCAP);
+				in_encap = nla_nest_start_noflag(skb,
+								 OVS_KEY_ATTR_ENCAP);
 				if (!swkey->eth.cvlan.tci)
 					goto unencap;
 			}
@@ -2226,7 +2227,7 @@ int ovs_nla_put_key(const struct sw_flow_key *swkey,
 	int err;
 	struct nlattr *nla;
 
-	nla = nla_nest_start(skb, attr);
+	nla = nla_nest_start_noflag(skb, attr);
 	if (!nla)
 		return -EMSGSIZE;
 	err = __ovs_nla_put_key(swkey, output, is_mask, skb);
@@ -3252,7 +3253,7 @@ static int sample_action_to_attr(const struct nlattr *attr,
 	const struct sample_arg *arg;
 	struct nlattr *actions;
 
-	start = nla_nest_start(skb, OVS_ACTION_ATTR_SAMPLE);
+	start = nla_nest_start_noflag(skb, OVS_ACTION_ATTR_SAMPLE);
 	if (!start)
 		return -EMSGSIZE;
 
@@ -3265,7 +3266,7 @@ static int sample_action_to_attr(const struct nlattr *attr,
 		goto out;
 	}
 
-	ac_start = nla_nest_start(skb, OVS_SAMPLE_ATTR_ACTIONS);
+	ac_start = nla_nest_start_noflag(skb, OVS_SAMPLE_ATTR_ACTIONS);
 	if (!ac_start) {
 		err = -EMSGSIZE;
 		goto out;
@@ -3291,7 +3292,7 @@ static int clone_action_to_attr(const struct nlattr *attr,
 	struct nlattr *start;
 	int err = 0, rem = nla_len(attr);
 
-	start = nla_nest_start(skb, OVS_ACTION_ATTR_CLONE);
+	start = nla_nest_start_noflag(skb, OVS_ACTION_ATTR_CLONE);
 	if (!start)
 		return -EMSGSIZE;
 
@@ -3313,7 +3314,7 @@ static int check_pkt_len_action_to_attr(const struct nlattr *attr,
 	const struct nlattr *a, *cpl_arg;
 	int err = 0, rem = nla_len(attr);
 
-	start = nla_nest_start(skb, OVS_ACTION_ATTR_CHECK_PKT_LEN);
+	start = nla_nest_start_noflag(skb, OVS_ACTION_ATTR_CHECK_PKT_LEN);
 	if (!start)
 		return -EMSGSIZE;
 
@@ -3332,8 +3333,8 @@ static int check_pkt_len_action_to_attr(const struct nlattr *attr,
 	 * 'OVS_CHECK_PKT_LEN_ATTR_ACTIONS_IF_LESS_EQUAL'.
 	 */
 	a = nla_next(cpl_arg, &rem);
-	ac_start =  nla_nest_start(skb,
-		OVS_CHECK_PKT_LEN_ATTR_ACTIONS_IF_LESS_EQUAL);
+	ac_start =  nla_nest_start_noflag(skb,
+					  OVS_CHECK_PKT_LEN_ATTR_ACTIONS_IF_LESS_EQUAL);
 	if (!ac_start) {
 		err = -EMSGSIZE;
 		goto out;
@@ -3351,8 +3352,8 @@ static int check_pkt_len_action_to_attr(const struct nlattr *attr,
 	 * OVS_CHECK_PKT_LEN_ATTR_ACTIONS_IF_GREATER.
 	 */
 	a = nla_next(a, &rem);
-	ac_start =  nla_nest_start(skb,
-				   OVS_CHECK_PKT_LEN_ATTR_ACTIONS_IF_GREATER);
+	ac_start =  nla_nest_start_noflag(skb,
+					  OVS_CHECK_PKT_LEN_ATTR_ACTIONS_IF_GREATER);
 	if (!ac_start) {
 		err = -EMSGSIZE;
 		goto out;
@@ -3386,7 +3387,7 @@ static int set_action_to_attr(const struct nlattr *a, struct sk_buff *skb)
 		struct ovs_tunnel_info *ovs_tun = nla_data(ovs_key);
 		struct ip_tunnel_info *tun_info = &ovs_tun->tun_dst->u.tun_info;
 
-		start = nla_nest_start(skb, OVS_ACTION_ATTR_SET);
+		start = nla_nest_start_noflag(skb, OVS_ACTION_ATTR_SET);
 		if (!start)
 			return -EMSGSIZE;
 
@@ -3418,7 +3419,7 @@ static int masked_set_action_to_set_action_attr(const struct nlattr *a,
 	/* Revert the conversion we did from a non-masked set action to
 	 * masked set action.
 	 */
-	nla = nla_nest_start(skb, OVS_ACTION_ATTR_SET);
+	nla = nla_nest_start_noflag(skb, OVS_ACTION_ATTR_SET);
 	if (!nla)
 		return -EMSGSIZE;