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, 5 insertions, 5 deletions

diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index ab119a7540db0f..39892e5d38a28b 100644
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -2916,7 +2916,7 @@ static const struct nla_policy ip_vs_dest_policy[IPVS_DEST_ATTR_MAX + 1] = {
 static int ip_vs_genl_fill_stats(struct sk_buff *skb, int container_type,
 				 struct ip_vs_kstats *kstats)
 {
-	struct nlattr *nl_stats = nla_nest_start(skb, container_type);
+	struct nlattr *nl_stats = nla_nest_start_noflag(skb, container_type);
 
 	if (!nl_stats)
 		return -EMSGSIZE;
@@ -2946,7 +2946,7 @@ nla_put_failure:
 static int ip_vs_genl_fill_stats64(struct sk_buff *skb, int container_type,
 				   struct ip_vs_kstats *kstats)
 {
-	struct nlattr *nl_stats = nla_nest_start(skb, container_type);
+	struct nlattr *nl_stats = nla_nest_start_noflag(skb, container_type);
 
 	if (!nl_stats)
 		return -EMSGSIZE;
@@ -2992,7 +2992,7 @@ static int ip_vs_genl_fill_service(struct sk_buff *skb,
 	struct ip_vs_kstats kstats;
 	char *sched_name;
 
-	nl_service = nla_nest_start(skb, IPVS_CMD_ATTR_SERVICE);
+	nl_service = nla_nest_start_noflag(skb, IPVS_CMD_ATTR_SERVICE);
 	if (!nl_service)
 		return -EMSGSIZE;
 
@@ -3203,7 +3203,7 @@ static int ip_vs_genl_fill_dest(struct sk_buff *skb, struct ip_vs_dest *dest)
 	struct nlattr *nl_dest;
 	struct ip_vs_kstats kstats;
 
-	nl_dest = nla_nest_start(skb, IPVS_CMD_ATTR_DEST);
+	nl_dest = nla_nest_start_noflag(skb, IPVS_CMD_ATTR_DEST);
 	if (!nl_dest)
 		return -EMSGSIZE;
 
@@ -3373,7 +3373,7 @@ static int ip_vs_genl_fill_daemon(struct sk_buff *skb, __u32 state,
 {
 	struct nlattr *nl_daemon;
 
-	nl_daemon = nla_nest_start(skb, IPVS_CMD_ATTR_DAEMON);
+	nl_daemon = nla_nest_start_noflag(skb, IPVS_CMD_ATTR_DAEMON);
 	if (!nl_daemon)
 		return -EMSGSIZE;