Merge dae73eaa9c into ed578af895

Before this commit: the printing of a rule results in
a pointer address.

After this commit: the printing of a rules results in
a human-readable text.

Resolves: #104

Signed-off-by: Paul Greenberg <greenpau@outlook.com>

.gitignore

@@ -0,0 +1 @@
+nftables.test

README.md

@@ -21,4 +21,12 @@ the data types/API will be identified as more functionality is added.
 
 Contributions are very welcome!
 
+### Testing Changes
 
+Run the following commands to test your changes:
+
+```bash
+go test ./...
+go test -c github.com/google/nftables
+sudo ./nftables.test -test.v -run_system_tests
+```

conn.go

@@ -37,16 +37,20 @@ type Conn struct {
 	TestDial nltest.Func // for testing only; passed to nltest.Dial
 	NetNS    int         // fd referencing the network namespace netlink will interact with.
 
-	lasting  bool       // establish a lasting connection to be used across multiple netlink operations.
+	lasting     bool       // establish a lasting connection to be used across multiple netlink operations.
-	mu       sync.Mutex // protects the following state
+	mu          sync.Mutex // protects the following state
-	messages []netlink.Message
+	messages    []netlink.Message
-	err      error
+	err         error
-	nlconn   *netlink.Conn // netlink socket using NETLINK_NETFILTER protocol.
+	nlconn      *netlink.Conn // netlink socket using NETLINK_NETFILTER protocol.
+	sockOptions []SockOption
 }
 
 // ConnOption is an option to change the behavior of the nftables Conn returned by Open.
 type ConnOption func(*Conn)
 
+// SockOption is an option to change the behavior of the netlink socket used by the nftables Conn.
+type SockOption func(*netlink.Conn) error
+
 // New returns a netlink connection for querying and modifying nftables. Some
 // aspects of the new netlink connection can be configured using the options
 // WithNetNSFd, WithTestDial, and AsLasting.
@@ -101,6 +105,14 @@ func WithTestDial(f nltest.Func) ConnOption {
 	}
 }
 
+// WithSockOptions sets the specified socket options when creating a new netlink
+// connection.
+func WithSockOptions(opts ...SockOption) ConnOption {
+	return func(cc *Conn) {
+		cc.sockOptions = append(cc.sockOptions, opts...)
+	}
+}
+
 // netlinkCloser is returned by netlinkConn(UnderLock) and must be called after
 // being done with the returned netlink connection in order to properly close
 // this connection, if necessary.
@@ -284,11 +296,28 @@ func (cc *Conn) FlushRuleset() {
 }
 
 func (cc *Conn) dialNetlink() (*netlink.Conn, error) {
+	var (
+		conn *netlink.Conn
+		err  error
+	)
+
 	if cc.TestDial != nil {
-		return nltest.Dial(cc.TestDial), nil
+		conn = nltest.Dial(cc.TestDial)
+	} else {
+		conn, err = netlink.Dial(unix.NETLINK_NETFILTER, &netlink.Config{NetNS: cc.NetNS})
 	}
 
-	return netlink.Dial(unix.NETLINK_NETFILTER, &netlink.Config{NetNS: cc.NetNS})
+	if err != nil {
+		return nil, err
+	}
+
+	for _, opt := range cc.sockOptions {
+		if err := opt(conn); err != nil {
+			return nil, err
+		}
+	}
+
+	return conn, nil
 }
 
 func (cc *Conn) setErr(err error) {

expr/verdict.go

@@ -24,6 +24,15 @@ import (
 	"golang.org/x/sys/unix"
 )
 
+const (
+	NFT_DROP   = 0
+	NFT_ACCEPT = 1
+	NFT_STOLEN = 2
+	NFT_QUEUE  = 3
+	NFT_REPEAT = 4
+	NFT_STOP   = 5
+)
+
 // This code assembles the verdict structure, as expected by the
 // nftables netlink API.
 // For further information, consult:
@@ -129,3 +138,37 @@ func (e *Verdict) unmarshal(fam byte, data []byte) error {
 	}
 	return ad.Err()
 }
+
+func (e *Verdict) String() string {
+	var v string
+	switch e.Kind {
+	case unix.NFT_RETURN:
+		v = "return" // -0x5
+	case unix.NFT_GOTO:
+		v = "goto" // -0x4
+	case unix.NFT_JUMP:
+		v = "jump" // NFT_JUMP = -0x3
+	case unix.NFT_BREAK:
+		v = "break" // NFT_BREAK = -0x2
+	case unix.NFT_CONTINUE:
+		v = "continue" // NFT_CONTINUE = -0x1
+	case NFT_DROP:
+		v = "drop"
+	case NFT_ACCEPT:
+		v = "accept"
+	case NFT_STOLEN:
+		v = "stolen"
+	case NFT_QUEUE:
+		v = "queue"
+	case NFT_REPEAT:
+		v = "repeat"
+	case NFT_STOP:
+		v = "stop"
+	default:
+		v = fmt.Sprintf("verdict %v", e.Kind)
+	}
+	if e.Chain != "" {
+		return v + " " + e.Chain
+	}
+	return v
+}

nftables_test.go

@@ -221,12 +221,27 @@ func TestRuleOperations(t *testing.T) {
 		expr.VerdictDrop,
 	}
 
+	wantStrings := []string{
+		"queue",
+		"accept",
+		"queue",
+		"accept",
+		"drop",
+		"drop",
+	}
+
 	for i, r := range rules {
 		rr, _ := r.Exprs[0].(*expr.Verdict)
 
 		if rr.Kind != want[i] {
 			t.Fatalf("bad verdict kind at %d", i)
 		}
+
+		if rr.String() != wantStrings[i] {
+			t.Fatalf("bad verdict string at %d: %s (received) vs. %s (expected)", i, rr.String(), wantStrings[i])
+		}
+
+		t.Logf("%s", rr)
 	}
 }
 

nftables_test.sh

@@ -0,0 +1,3 @@
+go test ./...
+go test -c github.com/google/nftables
+sudo ./nftables.test -test.v -run_system_tests