evaluate: add support for variables in map expressions

It is possible to use a variable to initialize a map, which is then used
in a map statement:

  define dst_map = { ::1234 : 5678 }

  table ip6 nat {
    map dst_map {
      typeof ip6 daddr : tcp dport;
      elements = $dst_map
    }
    chain prerouting {
      ip6 nexthdr tcp redirect to ip6 daddr map @dst_map
    }
  }

However, if one tries to use the variable directly in the statement:

  define dst_map = { ::1234 : 5678 }

  table ip6 nat {
    chain prerouting {
      ip6 nexthdr tcp redirect to ip6 daddr map $dst_map
    }
  }

nft rejects it:

  /space/azazel/tmp/ruleset.1067161.nft:5:47-54: Error: invalid mapping expression variable
      ip6 nexthdr tcp redirect to ip6 daddr map $dst_map
                                  ~~~~~~~~~     ^^^^^^^^
It also rejects variables in stateful object statements:

  define quota_map = { 192.168.10.123 : "user123", 192.168.10.124 : "user124" }

  table ip nat {
    quota user123 { over 20 mbytes }
    quota user124 { over 20 mbytes }
    chain prerouting {
      quota name ip saddr map $quota_map
    }
  }

thus:

  /space/azazel/tmp/ruleset.1067161.nft:15:29-38: Error: invalid mapping expression variable
      quota name ip saddr map $quota_map
                 ~~~~~~~~     ^^^^^^^^^^

Add support for these uses together with some test-cases.

Link: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1067161
Signed-off-by: Jeremy Sowden <jeremy@azazel.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 147 insertions, 0 deletions

diff --git a/tests/shell/testcases/maps/dumps/0024named_objects_1.json-nft b/tests/shell/testcases/maps/dumps/0024named_objects_1.json-nft
new file mode 100644
index 00000000..e3fab16d
--- /dev/null
+++ b/tests/shell/testcases/maps/dumps/0024named_objects_1.json-nft
@@ -0,0 +1,147 @@
+{
+  "nftables": [
+    {
+      "metainfo": {
+        "version": "VERSION",
+        "release_name": "RELEASE_NAME",
+        "json_schema_version": 1
+      }
+    },
+    {
+      "table": {
+        "family": "inet",
+        "name": "x",
+        "handle": 0
+      }
+    },
+    {
+      "chain": {
+        "family": "inet",
+        "table": "x",
+        "name": "y",
+        "handle": 0,
+        "type": "filter",
+        "hook": "input",
+        "prio": 0,
+        "policy": "accept"
+      }
+    },
+    {
+      "counter": {
+        "family": "inet",
+        "name": "user123",
+        "table": "x",
+        "handle": 0,
+        "packets": 12,
+        "bytes": 1433
+      }
+    },
+    {
+      "counter": {
+        "family": "inet",
+        "name": "user321",
+        "table": "x",
+        "handle": 0,
+        "packets": 12,
+        "bytes": 1433
+      }
+    },
+    {
+      "quota": {
+        "family": "inet",
+        "name": "user123",
+        "table": "x",
+        "handle": 0,
+        "bytes": 2000,
+        "used": 0,
+        "inv": true
+      }
+    },
+    {
+      "quota": {
+        "family": "inet",
+        "name": "user124",
+        "table": "x",
+        "handle": 0,
+        "bytes": 2000,
+        "used": 0,
+        "inv": true
+      }
+    },
+    {
+      "rule": {
+        "family": "inet",
+        "table": "x",
+        "chain": "y",
+        "handle": 0,
+        "expr": [
+          {
+            "counter": {
+              "map": {
+                "key": {
+                  "payload": {
+                    "protocol": "ip",
+                    "field": "saddr"
+                  }
+                },
+                "data": {
+                  "set": [
+                    [
+                      "1.1.1.1",
+                      "user123"
+                    ],
+                    [
+                      "2.2.2.2",
+                      "user123"
+                    ],
+                    [
+                      "192.168.2.2",
+                      "user123"
+                    ]
+                  ]
+                }
+              }
+            }
+          }
+        ]
+      }
+    },
+    {
+      "rule": {
+        "family": "inet",
+        "table": "x",
+        "chain": "y",
+        "handle": 0,
+        "expr": [
+          {
+            "quota": {
+              "map": {
+                "key": {
+                  "payload": {
+                    "protocol": "ip",
+                    "field": "saddr"
+                  }
+                },
+                "data": {
+                  "set": [
+                    [
+                      "192.168.2.2",
+                      "user124"
+                    ],
+                    [
+                      "192.168.2.3",
+                      "user124"
+                    ]
+                  ]
+                }
+              }
+            }
+          },
+          {
+            "drop": null
+          }
+        ]
+      }
+    }
+  ]
+}