evaluate: skip byteorder conversion for selector smaller than 2 bytes

Add unary expression to trigger byteorder conversion for host byteorder
selectors only if selectors length is larger or equal than 2 bytes.

 # cat test.nft
 table ip x {
        set test {
                type ipv4_addr . ether_addr . inet_proto
                flags interval
        }

        chain y {
                ip saddr . ether saddr . meta l4proto @test counter
        }
 }

 # nft -f test.nft
 ip x y
  [ meta load iiftype => reg 1 ]
  [ cmp eq reg 1 0x00000001 ]
  [ payload load 4b @ network header + 12 => reg 1 ]
  [ payload load 6b @ link header + 6 => reg 9 ]
  [ meta load l4proto => reg 11 ]
  [ byteorder reg 11 = hton(reg 11, 2, 1) ] <--- should not be here
  [ lookup reg 1 set test ]
  [ counter pkts 0 bytes 0 ]

Fixes: 1017d323cafa ("src: support for selectors with different byteorder with interval concatenations")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 41 insertions, 0 deletions

diff --git a/tests/py/inet/meta.t.json.output b/tests/py/inet/meta.t.json.output
index 3e7dd214..8697d5a2 100644
--- a/tests/py/inet/meta.t.json.output
+++ b/tests/py/inet/meta.t.json.output
@@ -51,3 +51,44 @@
     }
 ]
 
+# ip saddr . ether saddr . meta l4proto { 1.2.3.4 . aa:bb:cc:dd:ee:ff . 6 }
+[
+    {
+        "match": {
+            "left": {
+                "concat": [
+                    {
+                        "payload": {
+                            "field": "saddr",
+                            "protocol": "ip"
+                        }
+                    },
+                    {
+                        "payload": {
+                            "field": "saddr",
+                            "protocol": "ether"
+                        }
+                    },
+                    {
+                        "meta": {
+                            "key": "l4proto"
+                        }
+                    }
+                ]
+            },
+            "op": "==",
+            "right": {
+                "set": [
+                    {
+                        "concat": [
+                            "1.2.3.4",
+                            "aa:bb:cc:dd:ee:ff",
+                            6
+                        ]
+                    }
+                ]
+            }
+        }
+    }
+]
+