src: add support to add flowtables

This patch allows you to create flowtable:

 # nft add table x
 # nft add flowtable x m { hook ingress priority 10\; devices = { eth0, wlan0 }\; }

You have to specify hook and priority. So far, only the ingress hook is
supported. The priority represents where this flowtable is placed in the
ingress hook, which is registered to the devices that the user
specifies.

You can also use the 'create' command instead to bail out in case that
there is an existing flowtable with this name.

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

7 files changed, 228 insertions, 7 deletions

diff --git a/src/evaluate.c b/src/evaluate.c
index 6094d0c5..9da185c9 100644
--- a/src/evaluate.c
+++ b/src/evaluate.c
@@ -2910,6 +2910,24 @@ static int set_evaluate(struct eval_ctx *ctx, struct set *set)
 	return 0;
 }
 
+static uint32_t str2hooknum(uint32_t family, const char *hook);
+
+static int flowtable_evaluate(struct eval_ctx *ctx, struct flowtable *ft)
+{
+	struct table *table;
+
+	table = table_lookup_global(ctx);
+	if (table == NULL)
+		return cmd_error(ctx, "Could not process rule: Table '%s' does not exist",
+				 ctx->cmd->handle.table);
+
+	ft->hooknum = str2hooknum(NFPROTO_NETDEV, ft->hookstr);
+	if (ft->hooknum == NF_INET_NUMHOOKS)
+		return chain_error(ctx, ft, "invalid hook %s", ft->hookstr);
+
+	return 0;
+}
+
 static int rule_evaluate(struct eval_ctx *ctx, struct rule *rule)
 {
 	struct stmt *stmt, *tstmt = NULL;
@@ -3082,6 +3100,14 @@ static int cmd_evaluate_add(struct eval_ctx *ctx, struct cmd *cmd)
 		return chain_evaluate(ctx, cmd->chain);
 	case CMD_OBJ_TABLE:
 		return table_evaluate(ctx, cmd->table);
+	case CMD_OBJ_FLOWTABLE:
+		ret = cache_update(ctx->nf_sock, ctx->cache, cmd->op,
+				   ctx->msgs, ctx->debug_mask & NFT_DEBUG_NETLINK, ctx->octx);
+		if (ret < 0)
+			return ret;
+
+		handle_merge(&cmd->flowtable->handle, &cmd->handle);
+		return flowtable_evaluate(ctx, cmd->flowtable);
 	case CMD_OBJ_COUNTER:
 	case CMD_OBJ_QUOTA:
 	case CMD_OBJ_CT_HELPER:
diff --git a/src/expression.c b/src/expression.c
index ee75284e..d7f54ad7 100644
--- a/src/expression.c
+++ b/src/expression.c
@@ -702,8 +702,8 @@ struct expr *range_expr_alloc(const struct location *loc,
 	return expr;
 }
 
-static struct expr *compound_expr_alloc(const struct location *loc,
-					const struct expr_ops *ops)
+struct expr *compound_expr_alloc(const struct location *loc,
+				 const struct expr_ops *ops)
 {
 	struct expr *expr;
 
diff --git a/src/mnl.c b/src/mnl.c
index e70b0cde..be6e05da 100644
--- a/src/mnl.c
+++ b/src/mnl.c
@@ -1011,6 +1011,22 @@ err:
 	return NULL;
 }
 
+int mnl_nft_flowtable_batch_add(struct nftnl_flowtable *flo,
+				struct nftnl_batch *batch, unsigned int flags,
+				uint32_t seqnum)
+{
+	struct nlmsghdr *nlh;
+
+	nlh = nftnl_nlmsg_build_hdr(nftnl_batch_buffer(batch),
+				    NFT_MSG_NEWFLOWTABLE,
+				    nftnl_flowtable_get_u32(flo, NFTNL_FLOWTABLE_FAMILY),
+				    NLM_F_CREATE | flags, seqnum);
+	nftnl_flowtable_nlmsg_build_payload(nlh, flo);
+	mnl_nft_batch_continue(batch);
+
+	return 0;
+}
+
 /*
  * ruleset
  */
diff --git a/src/netlink.c b/src/netlink.c
index 9fadccd0..5b2d5e16 100644
--- a/src/netlink.c
+++ b/src/netlink.c
@@ -1489,6 +1489,64 @@ static struct obj *netlink_delinearize_obj(struct netlink_ctx *ctx,
 	return obj;
 }
 
+static struct nftnl_flowtable *alloc_nftnl_flowtable(const struct handle *h,
+						     const struct flowtable *ft)
+{
+	struct nftnl_flowtable *flo;
+
+	flo = nftnl_flowtable_alloc();
+	if (flo == NULL)
+		memory_allocation_error();
+
+	nftnl_flowtable_set_u32(flo, NFTNL_FLOWTABLE_FAMILY, h->family);
+	nftnl_flowtable_set_str(flo, NFTNL_FLOWTABLE_TABLE, h->table);
+	if (h->flowtable != NULL)
+		nftnl_flowtable_set_str(flo, NFTNL_FLOWTABLE_NAME, h->flowtable);
+
+	return flo;
+}
+
+static void netlink_dump_flowtable(struct nftnl_flowtable *flo,
+				   struct netlink_ctx *ctx)
+{
+	FILE *fp = ctx->octx->output_fp;
+
+	if (!(ctx->debug_mask & NFT_DEBUG_NETLINK) || !fp)
+		return;
+
+	nftnl_flowtable_fprintf(fp, flo, 0, 0);
+	fprintf(fp, "\n");
+}
+
+int netlink_add_flowtable(struct netlink_ctx *ctx, const struct handle *h,
+			  struct flowtable *ft, uint32_t flags)
+{
+	struct nftnl_flowtable *flo;
+	const char *dev_array[8];
+	struct expr *expr;
+	int i = 0, err;
+
+	flo = alloc_nftnl_flowtable(h, ft);
+	nftnl_flowtable_set_u32(flo, NFTNL_FLOWTABLE_HOOKNUM, ft->hooknum);
+	nftnl_flowtable_set_u32(flo, NFTNL_FLOWTABLE_PRIO, ft->priority);
+
+	list_for_each_entry(expr, &ft->dev_expr->expressions, list)
+		dev_array[i++] = expr->identifier;
+
+	dev_array[i] = NULL;
+	nftnl_flowtable_set_array(flo, NFTNL_FLOWTABLE_DEVICES, dev_array);
+
+	netlink_dump_flowtable(flo, ctx);
+
+	err = mnl_nft_flowtable_batch_add(flo, ctx->batch, flags, ctx->seqnum);
+	if (err < 0)
+		netlink_io_error(ctx, &ft->location, "Could not add flowtable: %s",
+				 strerror(errno));
+	nftnl_flowtable_free(flo);
+
+	return err;
+}
+
 static int list_obj_cb(struct nftnl_obj *nls, void *arg)
 {
 	struct netlink_ctx *ctx = arg;
diff --git a/src/parser_bison.y b/src/parser_bison.y
index faa613c2..c73eddde 100644
--- a/src/parser_bison.y
+++ b/src/parser_bison.y
@@ -146,6 +146,7 @@ int nft_lex(void *, void *, void *);
 	struct expr		*expr;
 	struct set		*set;
 	struct obj		*obj;
+	struct flowtable	*flowtable;
 	struct counter		*counter;
 	struct quota		*quota;
 	struct ct		*ct;
@@ -192,6 +193,7 @@ int nft_lex(void *, void *, void *);
 
 %token HOOK			"hook"
 %token DEVICE			"device"
+%token DEVICES			"devices"
 %token TABLE			"table"
 %token TABLES			"tables"
 %token CHAIN			"chain"
@@ -203,6 +205,7 @@ int nft_lex(void *, void *, void *);
 %token ELEMENT			"element"
 %token MAP			"map"
 %token MAPS			"maps"
+%token FLOWTABLE		"flowtable"
 %token HANDLE			"handle"
 %token RULESET			"ruleset"
 %token TRACE			"trace"
@@ -503,9 +506,9 @@ int nft_lex(void *, void *, void *);
 %type <cmd>			base_cmd add_cmd replace_cmd create_cmd insert_cmd delete_cmd list_cmd reset_cmd flush_cmd rename_cmd export_cmd monitor_cmd describe_cmd import_cmd
 %destructor { cmd_free($$); }	base_cmd add_cmd replace_cmd create_cmd insert_cmd delete_cmd list_cmd reset_cmd flush_cmd rename_cmd export_cmd monitor_cmd describe_cmd import_cmd
 
-%type <handle>			table_spec chain_spec chain_identifier ruleid_spec handle_spec position_spec rule_position ruleset_spec
-%destructor { handle_free(&$$); } table_spec chain_spec chain_identifier ruleid_spec handle_spec position_spec rule_position ruleset_spec
-%type <handle>			set_spec set_identifier obj_spec obj_identifier
+%type <handle>			table_spec chain_spec flowtable_spec chain_identifier ruleid_spec handle_spec position_spec rule_position ruleset_spec
+%destructor { handle_free(&$$); } table_spec chain_spec flowtable_spec chain_identifier ruleid_spec handle_spec position_spec rule_position ruleset_spec
+%type <handle>			set_spec set_identifier flowtable_identifier obj_spec obj_identifier
 %destructor { handle_free(&$$); } set_spec set_identifier obj_spec obj_identifier
 %type <val>			family_spec family_spec_explicit chain_policy prio_spec
 
@@ -529,6 +532,9 @@ int nft_lex(void *, void *, void *);
 %type <set>			map_block_alloc map_block
 %destructor { set_free($$); }	map_block_alloc
 
+%type <flowtable>		flowtable_block_alloc flowtable_block
+%destructor { flowtable_free($$); }	flowtable_block_alloc
+
 %type <obj>			obj_block_alloc counter_block quota_block ct_helper_block limit_block
 %destructor { obj_free($$); }	obj_block_alloc
 
@@ -609,8 +615,8 @@ int nft_lex(void *, void *, void *);
 %type <expr>			verdict_map_expr verdict_map_list_expr verdict_map_list_member_expr
 %destructor { expr_free($$); }	verdict_map_expr verdict_map_list_expr verdict_map_list_member_expr
 
-%type <expr>			set_expr set_block_expr set_list_expr set_list_member_expr
-%destructor { expr_free($$); }	set_expr set_block_expr set_list_expr set_list_member_expr
+%type <expr>			set_expr set_block_expr set_list_expr set_list_member_expr flowtable_expr flowtable_list_expr flowtable_expr_member
+%destructor { expr_free($$); }	set_expr set_block_expr set_list_expr set_list_member_expr flowtable_expr flowtable_list_expr flowtable_expr_member
 %type <expr>			set_elem_expr set_elem_expr_alloc set_lhs_expr set_rhs_expr
 %destructor { expr_free($$); }	set_elem_expr set_elem_expr_alloc set_lhs_expr set_rhs_expr
 %type <expr>			set_elem_expr_stmt set_elem_expr_stmt_alloc
@@ -895,6 +901,13 @@ add_cmd			:	TABLE		table_spec
 			{
 				$$ = cmd_alloc(CMD_ADD, CMD_OBJ_SETELEM, &$2, &@$, $3);
 			}
+			|	FLOWTABLE	flowtable_spec	flowtable_block_alloc
+						'{'	flowtable_block	'}'
+			{
+				$5->location = @5;
+				handle_merge(&$3->handle, &$2);
+				$$ = cmd_alloc(CMD_ADD, CMD_OBJ_FLOWTABLE, &$2, &@$, $5);
+			}
 			|	COUNTER		obj_spec
 			{
 				struct obj *obj;
@@ -970,6 +983,13 @@ create_cmd		:	TABLE		table_spec
 			{
 				$$ = cmd_alloc(CMD_CREATE, CMD_OBJ_SETELEM, &$2, &@$, $3);
 			}
+			|	FLOWTABLE	flowtable_spec	flowtable_block_alloc
+						'{'	flowtable_block	'}'
+			{
+				$5->location = @5;
+				handle_merge(&$3->handle, &$2);
+				$$ = cmd_alloc(CMD_CREATE, CMD_OBJ_FLOWTABLE, &$2, &@$, $5);
+			}
 			|	COUNTER		obj_spec
 			{
 				struct obj *obj;
@@ -1338,6 +1358,17 @@ table_block		:	/* empty */	{ $$ = $<table>-1; }
 				list_add_tail(&$4->list, &$1->sets);
 				$$ = $1;
 			}
+
+			|	table_block	FLOWTABLE	flowtable_identifier
+					flowtable_block_alloc	'{'	flowtable_block	'}'
+					stmt_separator
+			{
+				$4->location = @3;
+				handle_merge(&$4->handle, &$3);
+				handle_free(&$3);
+				list_add_tail(&$4->list, &$1->flowtables);
+				$$ = $1;
+			}
 			|	table_block	COUNTER		obj_identifier
 					obj_block_alloc	'{'	counter_block	'}'
 					stmt_separator
@@ -1538,6 +1569,62 @@ set_policy_spec		:	PERFORMANCE	{ $$ = NFT_SET_POL_PERFORMANCE; }
 			|	MEMORY		{ $$ = NFT_SET_POL_MEMORY; }
 			;
 
+flowtable_block_alloc	:	/* empty */
+			{
+				$$ = flowtable_alloc(NULL);
+			}
+			;
+
+flowtable_block		:	/* empty */	{ $$ = $<flowtable>-1; }
+			|	flowtable_block	common_block
+			|	flowtable_block	stmt_separator
+			|	flowtable_block	HOOK		STRING	PRIORITY        prio_spec	stmt_separator
+			{
+				$$->hookstr	= chain_hookname_lookup($3);
+				if ($$->hookstr == NULL) {
+					erec_queue(error(&@3, "unknown chain hook %s", $3),
+						   state->msgs);
+					xfree($3);
+					YYERROR;
+				}
+				xfree($3);
+
+				$$->priority = $5;
+			}
+			|	flowtable_block	DEVICES		'='	flowtable_expr	stmt_separator
+			{
+				$$->dev_expr = $4;
+			}
+			;
+
+flowtable_expr		:	'{'	flowtable_list_expr	'}'
+			{
+				$2->location = @$;
+				$$ = $2;
+			}
+			;
+
+flowtable_list_expr	:	flowtable_expr_member
+			{
+				$$ = compound_expr_alloc(&@$, NULL);
+				compound_expr_add($$, $1);
+			}
+			|	flowtable_list_expr	COMMA	flowtable_expr_member
+			{
+				compound_expr_add($1, $3);
+				$$ = $1;
+			}
+			|	flowtable_list_expr	COMMA	opt_newline
+			;
+
+flowtable_expr_member	:	STRING
+			{
+				$$ = symbol_expr_alloc(&@$, SYMBOL_VALUE,
+						       current_scope(state),
+						       $1);
+			}
+			;
+
 data_type_atom_expr	:	type_identifier
 			{
 				const struct datatype *dtype = datatype_lookup_byname($1);
@@ -1746,6 +1833,21 @@ set_identifier		:	identifier
 			}
 			;
 
+
+flowtable_spec		:	table_spec	identifier
+			{
+				$$		= $1;
+				$$.flowtable	= $2;
+			}
+			;
+
+flowtable_identifier	:	identifier
+			{
+				memset(&$$, 0, sizeof($$));
+				$$.flowtable	= $1;
+			}
+			;
+
 obj_spec		:	table_spec	identifier
 			{
 				$$		= $1;
diff --git a/src/rule.c b/src/rule.c
index 9c8d7f7d..5f1c35d5 100644
--- a/src/rule.c
+++ b/src/rule.c
@@ -45,6 +45,8 @@ void handle_merge(struct handle *dst, const struct handle *src)
 		dst->chain = xstrdup(src->chain);
 	if (dst->set == NULL && src->set != NULL)
 		dst->set = xstrdup(src->set);
+	if (dst->flowtable == NULL && src->flowtable != NULL)
+		dst->flowtable = xstrdup(src->flowtable);
 	if (dst->obj == NULL && src->obj != NULL)
 		dst->obj = xstrdup(src->obj);
 	if (dst->handle.id == 0)
@@ -899,6 +901,7 @@ struct cmd *cmd_alloc(enum cmd_ops op, enum cmd_obj obj,
 void nft_cmd_expand(struct cmd *cmd)
 {
 	struct list_head new_cmds;
+	struct flowtable *ft;
 	struct table *table;
 	struct chain *chain;
 	struct rule *rule;
@@ -938,6 +941,14 @@ void nft_cmd_expand(struct cmd *cmd)
 					&set->location, set_get(set));
 			list_add_tail(&new->list, &new_cmds);
 		}
+		list_for_each_entry(ft, &table->flowtables, list) {
+			handle_merge(&ft->handle, &table->handle);
+			memset(&h, 0, sizeof(h));
+			handle_merge(&h, &ft->handle);
+			new = cmd_alloc(CMD_ADD, CMD_OBJ_FLOWTABLE, &h,
+					&ft->location, flowtable_get(ft));
+			list_add_tail(&new->list, &new_cmds);
+		}
 		list_for_each_entry(chain, &table->chains, list) {
 			list_for_each_entry(rule, &chain->rules, list) {
 				memset(&h, 0, sizeof(h));
@@ -1024,6 +1035,9 @@ void cmd_free(struct cmd *cmd)
 		case CMD_OBJ_LIMIT:
 			obj_free(cmd->object);
 			break;
+		case CMD_OBJ_FLOWTABLE:
+			flowtable_free(cmd->flowtable);
+			break;
 		default:
 			BUG("invalid command object type %u\n", cmd->obj);
 		}
@@ -1115,6 +1129,9 @@ static int do_command_add(struct netlink_ctx *ctx, struct cmd *cmd, bool excl)
 	case CMD_OBJ_CT_HELPER:
 	case CMD_OBJ_LIMIT:
 		return netlink_add_obj(ctx, &cmd->handle, cmd->object, flags);
+	case CMD_OBJ_FLOWTABLE:
+		return netlink_add_flowtable(ctx, &cmd->handle, cmd->flowtable,
+					     flags);
 	default:
 		BUG("invalid command object type %u\n", cmd->obj);
 	}
diff --git a/src/scanner.l b/src/scanner.l
index 3ea33b09..79dccda2 100644
--- a/src/scanner.l
+++ b/src/scanner.l
@@ -240,6 +240,7 @@ addrstring	({macaddr}|{ip4addr}|{ip6addr})
 
 "hook"			{ return HOOK; }
 "device"		{ return DEVICE; }
+"devices"		{ return DEVICES; }
 "table"			{ return TABLE; }
 "tables"		{ return TABLES; }
 "chain"			{ return CHAIN; }
@@ -251,6 +252,7 @@ addrstring	({macaddr}|{ip4addr}|{ip6addr})
 "element"		{ return ELEMENT; }
 "map"			{ return MAP; }
 "maps"			{ return MAPS; }
+"flowtable"		{ return FLOWTABLE; }
 "handle"		{ return HANDLE; }
 "ruleset"		{ return RULESET; }
 "trace"			{ return TRACE; }