src: use cache infrastructure for set objects

This patch populates the cache only once through netlink_list_sets() during
evaluation. As a result, there is a single call to netlink_list_sets().

After this change, we can rid of get_set(). This function was fine by the time
we had no transaction support, but this doesn't work for set objects that are
declared in this batch, so inquiring the kernel doesn't help since they are not
yet available.

As a result from this update, the monitor code gets simplified quite a lot
since it can rely of the set cache. Moreover, we can now validate that the
table and set exists from evaluation path.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

2 files changed, 79 insertions, 86 deletions

diff --git a/src/evaluate.c b/src/evaluate.c
index 8b54dbc0..d5817f9b 100644
--- a/src/evaluate.c
+++ b/src/evaluate.c
@@ -109,37 +109,6 @@ static struct expr *implicit_set_declaration(struct eval_ctx *ctx,
 	return set_ref_expr_alloc(&expr->location, set);
 }
 
-// FIXME
-#include <netlink.h>
-static struct set *get_set(struct eval_ctx *ctx, const struct handle *h,
-			   const char *identifier)
-{
-	struct netlink_ctx nctx = {
-		.msgs = ctx->msgs,
-	};
-	struct handle handle;
-	struct set *set;
-	int err;
-
-	if (ctx->table != NULL) {
-		set = set_lookup(ctx->table, identifier);
-		if (set != NULL)
-			return set;
-	}
-
-	init_list_head(&nctx.list);
-
-	memset(&handle, 0, sizeof(handle));
-	handle_merge(&handle, h);
-	handle.set = xstrdup(identifier);
-	err = netlink_get_set(&nctx, &handle, &internal_location);
-	handle_free(&handle);
-
-	if (err < 0)
-		return NULL;
-	return list_first_entry(&nctx.list, struct set, list);
-}
-
 static enum ops byteorder_conversion_op(struct expr *expr,
 					enum byteorder byteorder)
 {
@@ -192,6 +161,7 @@ static int expr_evaluate_symbol(struct eval_ctx *ctx, struct expr **expr)
 {
 	struct error_record *erec;
 	struct symbol *sym;
+	struct table *table;
 	struct set *set;
 	struct expr *new;
 
@@ -213,9 +183,15 @@ static int expr_evaluate_symbol(struct eval_ctx *ctx, struct expr **expr)
 		new = expr_clone(sym->expr);
 		break;
 	case SYMBOL_SET:
-		set = get_set(ctx, &ctx->cmd->handle, (*expr)->identifier);
+		table = table_lookup(&ctx->cmd->handle);
+		if (table == NULL)
+			return cmd_error(ctx, "Could not process rule: Table '%s' does not exist",
+					 ctx->cmd->handle.table);
+
+		set = set_lookup(table, (*expr)->identifier);
 		if (set == NULL)
-			return -1;
+			return cmd_error(ctx, "Could not process rule: Set '%s' does not exist",
+					 (*expr)->identifier);
 		new = set_ref_expr_alloc(&(*expr)->location, set);
 		break;
 	}
@@ -1737,11 +1713,18 @@ int stmt_evaluate(struct eval_ctx *ctx, struct stmt *stmt)
 
 static int setelem_evaluate(struct eval_ctx *ctx, struct expr **expr)
 {
+	struct table *table;
 	struct set *set;
 
-	set = get_set(ctx, &ctx->cmd->handle, ctx->cmd->handle.set);
+	table = table_lookup(&ctx->cmd->handle);
+	if (table == NULL)
+		return cmd_error(ctx, "Could not process rule: Table '%s' does not exist",
+				 ctx->cmd->handle.table);
+
+	set = set_lookup(table, ctx->cmd->handle.set);
 	if (set == NULL)
-		return -1;
+		return cmd_error(ctx, "Could not process rule: Set '%s' does not exist",
+				 ctx->cmd->handle.set);
 
 	ctx->set = set;
 	expr_set_context(&ctx->ectx, set->keytype, set->keylen);
diff --git a/src/rule.c b/src/rule.c
index ccfde3de..741654bd 100644
--- a/src/rule.c
+++ b/src/rule.c
@@ -67,6 +67,22 @@ static int cache_init_tables(struct netlink_ctx *ctx, struct handle *h)
 	return 0;
 }
 
+static int cache_init_objects(struct netlink_ctx *ctx)
+{
+	struct table *table;
+	int ret;
+
+	list_for_each_entry(table, &table_list, list) {
+		ret = netlink_list_sets(ctx, &table->handle,
+					&internal_location);
+		list_splice_tail_init(&ctx->list, &table->sets);
+
+		if (ret < 0)
+			return -1;
+	}
+	return 0;
+}
+
 static int cache_init(enum cmd_ops cmd, struct list_head *msgs)
 {
 	struct handle handle = {
@@ -82,6 +98,9 @@ static int cache_init(enum cmd_ops cmd, struct list_head *msgs)
 	ret = cache_init_tables(&ctx, &handle);
 	if (ret < 0)
 		return ret;
+	ret = cache_init_objects(&ctx);
+	if (ret < 0)
+		return ret;
 
 	return 0;
 }
@@ -596,11 +615,14 @@ struct table *table_alloc(void)
 void table_free(struct table *table)
 {
 	struct chain *chain, *next;
+	struct set *set, *nset;
 
 	if (--table->refcnt > 0)
 		return;
 	list_for_each_entry_safe(chain, next, &table->chains, list)
 		chain_free(chain);
+	list_for_each_entry_safe(set, nset, &table->sets, list)
+		set_free(set);
 	handle_free(&table->handle);
 	scope_release(&table->scope);
 	xfree(table);
@@ -889,15 +911,11 @@ static int do_command_delete(struct netlink_ctx *ctx, struct cmd *cmd)
 static int do_list_sets(struct netlink_ctx *ctx, const struct location *loc,
 			struct table *table)
 {
-	struct set *set, *nset;
-
-	if (netlink_list_sets(ctx, &table->handle, loc) < 0)
-		return -1;
+	struct set *set;
 
-	list_for_each_entry_safe(set, nset, &ctx->list, list) {
+	list_for_each_entry(set, &table->sets, list) {
 		if (netlink_get_setelems(ctx, &set->handle, loc, set) < 0)
 			return -1;
-		list_move_tail(&set->list, &table->sets);
 	}
 	return 0;
 }
@@ -966,6 +984,23 @@ err:
 	return -1;
 }
 
+static int do_list_sets_global(struct netlink_ctx *ctx, struct cmd *cmd)
+{
+	struct table *table;
+	struct set *set;
+
+	list_for_each_entry(table, &table_list, list) {
+		list_for_each_entry(set, &table->sets, list) {
+			if (netlink_get_setelems(ctx, &set->handle,
+						 &cmd->location, set) < 0)
+				return -1;
+
+			set_print(set);
+		}
+	}
+	return 0;
+}
+
 static int do_list_ruleset(struct netlink_ctx *ctx, struct cmd *cmd)
 {
 	unsigned int family = cmd->handle.family;
@@ -998,10 +1033,25 @@ static int do_list_tables(struct netlink_ctx *ctx, struct cmd *cmd)
 	return 0;
 }
 
+static int do_list_set(struct netlink_ctx *ctx, struct cmd *cmd,
+		       struct table *table)
+{
+	struct set *set;
+
+	set = set_lookup(table, cmd->handle.set);
+	if (set == NULL)
+		return -1;
+
+	if (netlink_get_setelems(ctx, &cmd->handle, &cmd->location, set) < 0)
+		return -1;
+
+	set_print(set);
+	return 0;
+}
+
 static int do_command_list(struct netlink_ctx *ctx, struct cmd *cmd)
 {
 	struct table *table = NULL;
-	struct set *set;
 
 	if (cmd->handle.table != NULL)
 		table = table_lookup(&cmd->handle);
@@ -1014,28 +1064,9 @@ static int do_command_list(struct netlink_ctx *ctx, struct cmd *cmd)
 	case CMD_OBJ_CHAIN:
 		return do_list_table(ctx, cmd, table);
 	case CMD_OBJ_SETS:
-		if (netlink_list_sets(ctx, &cmd->handle, &cmd->location) < 0)
-			return -1;
-
-		list_for_each_entry(set, &ctx->list, list){
-			if (netlink_get_setelems(ctx, &set->handle,
-						 &cmd->location, set) < 0) {
-				return -1;
-			}
-			set_print(set);
-		}
-		return 0;
+		return do_list_sets_global(ctx, cmd);
 	case CMD_OBJ_SET:
-		if (netlink_get_set(ctx, &cmd->handle, &cmd->location) < 0)
-			goto err;
-		list_for_each_entry(set, &ctx->list, list) {
-			if (netlink_get_setelems(ctx, &cmd->handle,
-						 &cmd->location, set) < 0) {
-				goto err;
-			}
-			set_print(set);
-		}
-		return 0;
+		return do_list_set(ctx, cmd, table);
 	case CMD_OBJ_RULESET:
 		return do_list_ruleset(ctx, cmd);
 	default:
@@ -1043,9 +1074,6 @@ static int do_command_list(struct netlink_ctx *ctx, struct cmd *cmd)
 	}
 
 	return 0;
-err:
-	table_cleanup(table);
-	return -1;
 }
 
 static int do_command_flush(struct netlink_ctx *ctx, struct cmd *cmd)
@@ -1088,10 +1116,7 @@ static int do_command_rename(struct netlink_ctx *ctx, struct cmd *cmd)
 static int do_command_monitor(struct netlink_ctx *ctx, struct cmd *cmd)
 {
 	struct table *t;
-	struct set *s, *ns;
-	struct netlink_ctx set_ctx;
-	LIST_HEAD(msgs);
-	struct handle set_handle;
+	struct set *s;
 	struct netlink_mon_handler monhandler;
 
 	/* cache only needed if monitoring:
@@ -1106,24 +1131,9 @@ static int do_command_monitor(struct netlink_ctx *ctx, struct cmd *cmd)
 		monhandler.cache_needed = false;
 
 	if (monhandler.cache_needed) {
-		memset(&set_ctx, 0, sizeof(set_ctx));
-		init_list_head(&msgs);
-		set_ctx.msgs = &msgs;
-
 		list_for_each_entry(t, &table_list, list) {
-			set_handle.family = t->handle.family;
-			set_handle.table = t->handle.table;
-
-			init_list_head(&set_ctx.list);
-
-			if (netlink_list_sets(&set_ctx, &set_handle,
-					      &cmd->location) < 0)
-				return -1;
-
-			list_for_each_entry_safe(s, ns, &set_ctx.list, list) {
+			list_for_each_entry(s, &t->sets, list)
 				s->init = set_expr_alloc(&cmd->location);
-				set_add_hash(s, t);
-			}
 		}
 	}