payload: disable payload merge if offsets are not on byte boundary.

... because it doesn't work, we attempt to merge it into wrong
place, we would have to merge the second value at a specific location.

F.e. vlan hdr 4094 gives us

0xfe0f

Merging in the CFI should yield 0xfe1f, but the constant merging
doesn't know how to achive that; at the moment 'vlan id 4094'
and 'vlan id 4094 vlan cfi 1' give same result -- 0xfe0f.

For now just turn off the optimization step unless everything is
byte divisible (the common case).

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

diff --git a/src/payload.c b/src/payload.c
index 62f1d56da68215af638cd2d2ace64952db0baba3..880b5d0d0b9708eded6c0cb9073366e8f5b5d15a 100644 (file)
--- a/src/payload.c
+++ b/src/payload.c
@@ -357,6 +357,10 @@ raw:
  */
 bool payload_is_adjacent(const struct expr *e1, const struct expr *e2)
 {
+       if (e1->payload.offset % BITS_PER_BYTE || e1->len % BITS_PER_BYTE ||
+           e2->payload.offset % BITS_PER_BYTE || e2->len % BITS_PER_BYTE)
+               return false;
+
        if (e1->payload.base             == e2->payload.base &&
            e1->payload.offset + e1->len == e2->payload.offset)
                return true;