parser: restrict queue num expressiveness

Else we run into trouble once we allow
queue num symhash mod 4 and 1

and so on.  Example problem:

queue num jhash ip saddr mod 4 and 1 bypass

This will fail to parse because the scanner is in the wrong state
(ip, not queue), so 'bypass' is parsed as a string.

Currently, while nft will eat the above just fine (minus 'bypass'),
nft rejects this from the evaluation phase with
   Error: queue number is not constant

So seems we are lucky and can restrict the supported expressions
to integer and range.

Furthermore, the line looks wrong because this statement:

   queue num jhash ip saddr mod 4 and 1 bypass

doesn't specifiy a number, "queue num 4" does, or "queue num 1-2" do.

For arbitrary expr support it seems sensible to enforce stricter
ordering to avoid any problems with the flags, for example:

queue bypass,futurekeyword to jhash ip saddr mod 42

Signed-off-by: Florian Westphal <fw@strlen.de>

diff --git a/src/parser_bison.y b/src/parser_bison.y
index 5e702a054f44f69d0fbd1034cf4a5bebb870d80d..a329538a5ca889bf7debcc5705566bd064931c6d 100644 (file)
--- a/src/parser_bison.y
+++ b/src/parser_bison.y
@@ -705,6 +705,8 @@ int nft_lex(void *, void *, void *);
 
 %type <stmt>                   queue_stmt queue_stmt_alloc
 %destructor { stmt_free($$); } queue_stmt queue_stmt_alloc
+%type <expr>                   queue_stmt_expr
+%destructor { expr_free($$); } queue_stmt_expr
 %type <val>                    queue_stmt_flags queue_stmt_flag
 %type <stmt>                   dup_stmt
 %destructor { stmt_free($$); } dup_stmt
@@ -3753,7 +3755,7 @@ queue_stmt_args           :       queue_stmt_arg
                        |       queue_stmt_args queue_stmt_arg
                        ;
 
-queue_stmt_arg         :       QUEUENUM        stmt_expr
+queue_stmt_arg         :       QUEUENUM        queue_stmt_expr
                        {
                                $<stmt>0->queue.queue = $2;
                                $<stmt>0->queue.queue->location = @$;
@@ -3764,6 +3766,10 @@ queue_stmt_arg           :       QUEUENUM        stmt_expr
                        }
                        ;
 
+queue_stmt_expr                :       integer_expr
+                       |       range_rhs_expr
+                       ;
+
 queue_stmt_flags       :       queue_stmt_flag
                        |       queue_stmt_flags        COMMA   queue_stmt_flag
                        {