netlink: fix prefix expression handling

The prefix expression handling is full of bugs:

- netlink_gen_data() is used to construct the prefix mask from the full
  prefix expression. This is both conceptually wrong, the prefix expression
  is *not* data, and buggy, it only assumes network masks and thus only
  handles big endian types.

- Prefix expression reconstruction doesn't check whether the mask is a
  valid prefix and reconstructs crap otherwise. It doesn't reconstruct
  prefixes for anything but network addresses. On top of that its
  needlessly complicated, using the mpz values directly its a simple
  matter of finding the sequence of 1's that extend up to the full width.

- Unnecessary cloning of expressions where a simple refcount increase would
  suffice.

Rewrite that code properly.

Signed-off-by: Patrick McHardy <kaber@trash.net>

1 files changed, 0 insertions, 27 deletions

diff --git a/src/netlink.c b/src/netlink.c
index 6e797dcf..07af1cb8 100644
--- a/src/netlink.c
+++ b/src/netlink.c
@@ -252,31 +252,6 @@ static void netlink_gen_verdict(const struct expr *expr,
 	}
 }
 
-static void netlink_gen_prefix(const struct expr *expr,
-			       struct nft_data_linearize *data)
-{
-	uint32_t idx;
-	int32_t i, cidr;
-	uint32_t mask;
-
-	assert(expr->ops->type == EXPR_PREFIX);
-
-	data->len = div_round_up(expr->prefix->len, BITS_PER_BYTE);
-	cidr = expr->prefix_len;
-
-	for (i = 0; (uint32_t)i / BITS_PER_BYTE < data->len; i += 32) {
-		if (cidr - i >= 32)
-			mask = 0xffffffff;
-		else if (cidr - i > 0)
-			mask = (1 << (cidr - i)) - 1;
-		else
-			mask = 0;
-
-		idx = i / 32;
-		data->value[idx] = mask;
-	}
-}
-
 void netlink_gen_data(const struct expr *expr, struct nft_data_linearize *data)
 {
 	switch (expr->ops->type) {
@@ -286,8 +261,6 @@ void netlink_gen_data(const struct expr *expr, struct nft_data_linearize *data)
 		return netlink_gen_concat_data(expr, data);
 	case EXPR_VERDICT:
 		return netlink_gen_verdict(expr, data);
-	case EXPR_PREFIX:
-		return netlink_gen_prefix(expr, data);
 	default:
 		BUG("invalid data expression type %s\n", expr->ops->name);
 	}