netfilter: nfnetlink: New NFNLA_HOOK_INFO_DESC helper

Introduce a helper routine adding the nested attribute for use by a
second caller later.

Note how this introduces cancelling of 'nest2' for categorical reasons.
Since always followed by cancelling of the outer 'nest', it is
technically not needed.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/net/netfilter/nfnetlink_hook.c b/net/netfilter/nfnetlink_hook.c
index ade8ee1988b1eb180d3042b93f17637aa31c2a43..cd4056527ede7b87eee2435441050dfd08097cf5 100644 (file)
--- a/net/netfilter/nfnetlink_hook.c
+++ b/net/netfilter/nfnetlink_hook.c
@@ -109,13 +109,30 @@ cancel_nest:
        return -EMSGSIZE;
 }
 
+static int nfnl_hook_put_nft_info_desc(struct sk_buff *nlskb, const char *tname,
+                                      const char *name, u8 family)
+{
+       struct nlattr *nest;
+
+       nest = nla_nest_start(nlskb, NFNLA_HOOK_INFO_DESC);
+       if (!nest ||
+           nla_put_string(nlskb, NFNLA_CHAIN_TABLE, tname) ||
+           nla_put_string(nlskb, NFNLA_CHAIN_NAME, name) ||
+           nla_put_u8(nlskb, NFNLA_CHAIN_FAMILY, family)) {
+               nla_nest_cancel(nlskb, nest);
+               return -EMSGSIZE;
+       }
+       nla_nest_end(nlskb, nest);
+       return 0;
+}
+
 static int nfnl_hook_put_nft_chain_info(struct sk_buff *nlskb,
                                        const struct nfnl_dump_hook_data *ctx,
                                        unsigned int seq,
                                        struct nft_chain *chain)
 {
        struct net *net = sock_net(nlskb->sk);
-       struct nlattr *nest, *nest2;
+       struct nlattr *nest;
        int ret = 0;
 
        if (WARN_ON_ONCE(!chain))
@@ -128,29 +145,15 @@ static int nfnl_hook_put_nft_chain_info(struct sk_buff *nlskb,
        if (!nest)
                return -EMSGSIZE;
 
-       nest2 = nla_nest_start(nlskb, NFNLA_HOOK_INFO_DESC);
-       if (!nest2)
-               goto cancel_nest;
-
-       ret = nla_put_string(nlskb, NFNLA_CHAIN_TABLE, chain->table->name);
-       if (ret)
-               goto cancel_nest;
-
-       ret = nla_put_string(nlskb, NFNLA_CHAIN_NAME, chain->name);
-       if (ret)
-               goto cancel_nest;
-
-       ret = nla_put_u8(nlskb, NFNLA_CHAIN_FAMILY, chain->table->family);
-       if (ret)
-               goto cancel_nest;
+       ret = nfnl_hook_put_nft_info_desc(nlskb, chain->table->name,
+                                         chain->name, chain->table->family);
+       if (ret) {
+               nla_nest_cancel(nlskb, nest);
+               return ret;
+       }
 
-       nla_nest_end(nlskb, nest2);
        nla_nest_end(nlskb, nest);
-       return ret;
-
-cancel_nest:
-       nla_nest_cancel(nlskb, nest);
-       return -EMSGSIZE;
+       return 0;
 }
 
 static int nfnl_hook_dump_one(struct sk_buff *nlskb,