cache: Filter chain list on kernel side

When operating on a specific chain, add payload to NFT_MSG_GETCHAIN so
kernel returns only relevant data. Since ENOENT is an expected return
code, do not treat this as error.

While being at it, improve code in chain_cache_cb() a bit:
- Check chain's family first, it is a less expensive check than
  comparing table names.
- Do not extract chain name of uninteresting chains.

Signed-off-by: Phil Sutter <phil@nwl.cc>

1 files changed, 2 insertions, 1 deletions

diff --git a/include/mnl.h b/include/mnl.h
index 19faa651..9d54aac8 100644
--- a/include/mnl.h
+++ b/include/mnl.h
@@ -43,7 +43,8 @@ int mnl_nft_chain_rename(struct netlink_ctx *ctx, const struct cmd *cmd,
 			 const struct chain *chain);
 
 struct nftnl_chain_list *mnl_nft_chain_dump(struct netlink_ctx *ctx,
-					    int family);
+					    int family, const char *table,
+					    const char *chain);
 
 int mnl_nft_table_add(struct netlink_ctx *ctx, struct cmd *cmd,
 		      unsigned int flags);