Hi Florian,
On Tue, May 23, 2023 at 07:29:31PM +0200, Florian Westphal wrote:
> Hello.
>
> Consider following example:
>
> table ip t {
> set s {
> type ipv4_addr . ipv4_addr . inet_service
> size 65535
> flags dynamic, timeout
> timeout 3h
> }
>
> chain c1 {
> update @s { ip saddr . 10.180.0.4 . 80 }
> }
>
> chain c2 {
> ip saddr . 1.2.3.4 . 80 @s goto c1
> }
> }
>
> This doesn't work:
> :13:14-20: Error: Can't parse symbolic invalid expressions
> ip saddr . 1.2.3.4 . 80 @s goto c1
>
> Problem is that expr_evaluate_relational() first evaluates
> the lhs, so by the time concat evaluation encounters '1.2.3.4'
> symbol there is nothing that would hint at what datatype that is.
>
> For this specific case, its possible to first evaluate the rhs, i.e.:
>
> --- a/src/evaluate.c
> +++ b/src/evaluate.c
> @@ -2336,8 +2336,15 @@ static int expr_evaluate_relational(struct eval_ctx *ctx, struct expr **expr)
> struct expr *range;
> int ret;
>
> + right = rel->right;
> + if (right->etype == EXPR_SYMBOL &&
> + right->symtype == SYMBOL_SET &&
> + expr_evaluate(ctx, &rel->right) < 0)
> + return -1;
> +
>
> This populates ectx->key and thus allows to infer the symbolic data
> type:
>
> 1485 if (key) {
> 1486 tmp = key->dtype;
> 1487 dsize = key->len;
> 1488 bo = key->byteorder;
> 1489 off--;
> 1490 } else if (dtype == NULL || off == 0) {
> 1491 tmp = datatype_lookup(TYPE_INVALID);
>
> line 1486ff. With unmodified nft, this hits the 'dtype == NULL' path
> and decoding "1.2.3.4" fails.
>
> What do you think? If you think this is fine I can work on this,
> above patch makes nft parse the example above, it needs more work on
> delinarization path.
If you have a use-case for this, go ahead.
Is there any other issue you can forecast on the delinearize path? Or
is it just that the code to handle this is missing?
Thanks.
