[PATCH nft 1/3] expression: missing != in flagcmp expression print function

[Pablo Neira Ayuso <pablo@netfilter.org>]

Missing != when printing the expression.

Fixes: c3d57114f119 ("parser_bison: add shortcut syntax for matching flags without binary operations")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 src/expression.c            |  7 ++++++-
 tests/py/inet/tcp.t         |  1 +
 tests/py/inet/tcp.t.json    | 25 +++++++++++++++++++++++++
 tests/py/inet/tcp.t.payload |  8 ++++++++
 4 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/src/expression.c b/src/expression.c
index c6be000107f2..4c0874fe9950 100644
--- a/src/expression.c
+++ b/src/expression.c
@@ -1358,7 +1358,12 @@ struct expr *set_elem_catchall_expr_alloc(const struct location *loc)
 static void flagcmp_expr_print(const struct expr *expr, struct output_ctx *octx)
 {
 	expr_print(expr->flagcmp.expr, octx);
-	nft_print(octx, " ");
+
+	if (expr->op == OP_NEQ)
+		nft_print(octx, " != ");
+	else
+		nft_print(octx, " ");
+
 	expr_print(expr->flagcmp.value, octx);
 	nft_print(octx, " / ");
 	expr_print(expr->flagcmp.mask, octx);
diff --git a/tests/py/inet/tcp.t b/tests/py/inet/tcp.t
index 532da2776d24..16e15b9f76c1 100644
--- a/tests/py/inet/tcp.t
+++ b/tests/py/inet/tcp.t
@@ -68,6 +68,7 @@ tcp flags cwr;ok
 tcp flags != cwr;ok
 tcp flags == syn;ok
 tcp flags fin,syn / fin,syn;ok
+tcp flags != syn / fin,syn;ok
 tcp flags & (fin | syn | rst | psh | ack | urg | ecn | cwr) == fin | syn | rst | psh | ack | urg | ecn | cwr;ok;tcp flags == 0xff
 tcp flags { syn, syn | ack };ok
 tcp flags & (fin | syn | rst | psh | ack | urg) == { fin, ack, psh | ack, fin | psh | ack };ok
diff --git a/tests/py/inet/tcp.t.json b/tests/py/inet/tcp.t.json
index 8c2a376b2e60..590a3dee5d3f 100644
--- a/tests/py/inet/tcp.t.json
+++ b/tests/py/inet/tcp.t.json
@@ -1496,3 +1496,28 @@
         }
     }
 ]
+
+# tcp flags != syn / fin,syn
+[
+    {
+        "match": {
+            "left": {
+                "&": [
+                    {
+                        "payload": {
+                            "field": "flags",
+                            "protocol": "tcp"
+                        }
+                    },
+                    [
+                        "fin",
+                        "syn"
+                    ]
+                ]
+            },
+            "op": "!=",
+            "right": "syn"
+        }
+    }
+]
+
diff --git a/tests/py/inet/tcp.t.payload b/tests/py/inet/tcp.t.payload
index ee61b1a722d5..7f302080f02a 100644
--- a/tests/py/inet/tcp.t.payload
+++ b/tests/py/inet/tcp.t.payload
@@ -362,6 +362,14 @@ inet test-inet input
   [ bitwise reg 1 = ( reg 1 & 0x00000003 ) ^ 0x00000000 ]
   [ cmp eq reg 1 0x00000003 ]
 
+# tcp flags != syn / fin,syn
+inet test-inet input
+  [ meta load l4proto => reg 1 ]
+  [ cmp eq reg 1 0x00000006 ]
+  [ payload load 1b @ transport header + 13 => reg 1 ]
+  [ bitwise reg 1 = ( reg 1 & 0x00000003 ) ^ 0x00000000 ]
+  [ cmp neq reg 1 0x00000002 ]
+
 # tcp flags & (fin | syn | rst | psh | ack | urg | ecn | cwr) == fin | syn | rst | psh | ack | urg | ecn | cwr
 inet test-inet input
   [ meta load l4proto => reg 1 ]
-- 
2.20.1