cache: Filter rule list on kernel side

Instead of fetching all existing rules in kernel's ruleset and filtering
in user space, add payload to the dump request specifying the table and
chain to filter for.

Since list_rule_cb() no longer needs the filter, pass only netlink_ctx
to the callback and drop struct rule_cache_dump_ctx.

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

3 files changed, 24 insertions, 24 deletions

diff --git a/include/mnl.h b/include/mnl.h
index 344030f3..19faa651 100644
--- a/include/mnl.h
+++ b/include/mnl.h
@@ -33,8 +33,8 @@ int mnl_nft_rule_add(struct netlink_ctx *ctx, struct cmd *cmd,
 int mnl_nft_rule_del(struct netlink_ctx *ctx, struct cmd *cmd);
 int mnl_nft_rule_replace(struct netlink_ctx *ctx, struct cmd *cmd);
 
-struct nftnl_rule_list *mnl_nft_rule_dump(struct netlink_ctx *ctx,
-					  int family);
+struct nftnl_rule_list *mnl_nft_rule_dump(struct netlink_ctx *ctx, int family,
+					  const struct nft_cache_filter *filter);
 
 int mnl_nft_chain_add(struct netlink_ctx *ctx, struct cmd *cmd,
 		      unsigned int flags);
diff --git a/src/cache.c b/src/cache.c
index 66da2b34..484efdb9 100644
--- a/src/cache.c
+++ b/src/cache.c
@@ -441,16 +441,9 @@ struct chain *chain_cache_find(const struct table *table, const char *name)
 	return NULL;
 }
 
-struct rule_cache_dump_ctx {
-	struct netlink_ctx	*nlctx;
-	const struct nft_cache_filter *filter;
-};
-
 static int list_rule_cb(struct nftnl_rule *nlr, void *data)
 {
-	struct rule_cache_dump_ctx *rule_ctx = data;
-	const struct nft_cache_filter *filter = rule_ctx->filter;
-	struct netlink_ctx *ctx = rule_ctx->nlctx;
+	struct netlink_ctx *ctx = data;
 	const struct handle *h = ctx->data;
 	const char *table, *chain;
 	struct rule *rule;
@@ -465,12 +458,6 @@ static int list_rule_cb(struct nftnl_rule *nlr, void *data)
 	    (h->chain.name && strcmp(chain, h->chain.name) != 0))
 		return 0;
 
-	if (filter && filter->list.table && filter->list.chain &&
-	    (filter->list.family != family ||
-	     strcmp(filter->list.table, table) ||
-	     strcmp(filter->list.chain, chain)))
-		return 0;
-
 	netlink_dump_rule(nlr, ctx);
 	rule = netlink_delinearize_rule(ctx, nlr);
 	list_add_tail(&rule->list, &ctx->list);
@@ -481,13 +468,9 @@ static int list_rule_cb(struct nftnl_rule *nlr, void *data)
 static int rule_cache_init(struct netlink_ctx *ctx, const struct handle *h,
 			   const struct nft_cache_filter *filter)
 {
-	struct rule_cache_dump_ctx rule_ctx = {
-		.nlctx = ctx,
-		.filter = filter,
-	};
 	struct nftnl_rule_list *rule_cache;
 
-	rule_cache = mnl_nft_rule_dump(ctx, h->family);
+	rule_cache = mnl_nft_rule_dump(ctx, h->family, filter);
 	if (rule_cache == NULL) {
 		if (errno == EINTR)
 			return -1;
@@ -496,7 +479,7 @@ static int rule_cache_init(struct netlink_ctx *ctx, const struct handle *h,
 	}
 
 	ctx->data = h;
-	nftnl_rule_list_foreach(rule_cache, list_rule_cb, &rule_ctx);
+	nftnl_rule_list_foreach(rule_cache, list_rule_cb, ctx);
 	nftnl_rule_list_free(rule_cache);
 	return 0;
 }
diff --git a/src/mnl.c b/src/mnl.c
index 21b98e34..26f643fb 100644
--- a/src/mnl.c
+++ b/src/mnl.c
@@ -653,20 +653,37 @@ err_free:
 	return MNL_CB_OK;
 }
 
-struct nftnl_rule_list *mnl_nft_rule_dump(struct netlink_ctx *ctx,
-					  int family)
+struct nftnl_rule_list *mnl_nft_rule_dump(struct netlink_ctx *ctx, int family,
+					  const struct nft_cache_filter *filter)
 {
 	char buf[MNL_SOCKET_BUFFER_SIZE];
 	struct nftnl_rule_list *nlr_list;
+	struct nftnl_rule *nlr = NULL;
 	struct nlmsghdr *nlh;
 	int ret;
 
+	if (filter && filter->list.table) {
+		nlr = nftnl_rule_alloc();
+		if (!nlr)
+			memory_allocation_error();
+
+		nftnl_rule_set_str(nlr, NFTNL_RULE_TABLE,
+				   filter->list.table);
+		if (filter->list.chain)
+			nftnl_rule_set_str(nlr, NFTNL_RULE_CHAIN,
+					   filter->list.chain);
+	}
+
 	nlr_list = nftnl_rule_list_alloc();
 	if (nlr_list == NULL)
 		memory_allocation_error();
 
 	nlh = nftnl_nlmsg_build_hdr(buf, NFT_MSG_GETRULE, family,
 				    NLM_F_DUMP, ctx->seqnum);
+	if (nlr) {
+		nftnl_rule_nlmsg_build_payload(nlh, nlr);
+		nftnl_rule_free(nlr);
+	}
 
 	ret = nft_mnl_talk(ctx, nlh, nlh->nlmsg_len, rule_cb, nlr_list);
 	if (ret < 0)