netlink: fix flags dissection

Flags are not in network byte order, use given encoding instead.

Show both flags fields for GET and NEW requests since the netlink
dissector cannot yet determine whether a request is for GET, NEW or
something else. This has no effect for the sockdiag dissector but it
will influence the route and netfilter netlink subdissectors.

Change-Id: I472ff9e0498debbbceef657a14408c4e6a9df75b
Reviewed-on: https://code.wireshark.org/review/17118
Reviewed-by: Anders Broman <a.broman58@gmail.com>

diff --git a/epan/dissectors/packet-netlink.c b/epan/dissectors/packet-netlink.c
index ca9a3c5fe4308788b2ddc22161bb2e3ad5fce02b..b939adac13bb0a1c7d093b5008d703a442288ed1 100644 (file)
--- a/epan/dissectors/packet-netlink.c
+++ b/epan/dissectors/packet-netlink.c
@@ -225,6 +225,16 @@ static const int *netlink_header_new_flags[] = {
        NULL
 };
 
+static const int *netlink_header_standard_flags[] = {
+       &hfi_netlink_hdr_flag_request.id,
+       &hfi_netlink_hdr_flag_multi.id,
+       &hfi_netlink_hdr_flag_ack.id,
+       &hfi_netlink_hdr_flag_echo.id,
+       &hfi_netlink_hdr_flag_dumpintr.id,
+       &hfi_netlink_hdr_flag_dumpfiltered.id,
+       NULL
+};
+
 
 int
 dissect_netlink_attributes(tvbuff_t *tvb, header_field_info *hfi_type, int ett, void *data, proto_tree *tree, int offset, int length, netlink_attributes_cb_t cb)
@@ -318,14 +328,17 @@ dissect_netlink_hdr(tvbuff_t *tvb, proto_tree *tree, int offset, int encoding, g
        }
        offset += 2;
 
-       hdr_flags = tvb_get_letohs(tvb, offset);
-       if(hdr_flags & WS_NLM_F_REQUEST) {
+       hdr_flags = tvb_get_guint16(tvb, offset, encoding);
+       if ((hdr_flags & WS_NLM_F_REQUEST) && (hdr_flags & 0x0f00)) {
+               /* XXX detect based on the protocol family and message type
+                * whether this is a GET, NEW or regular request. */
                proto_tree_add_bitmask(fh_hdr, tvb, offset, hfi_netlink_hdr_flags.id,
-                       ett_netlink_hdr_flags, netlink_header_get_flags, ENC_BIG_ENDIAN);
-       }
-       else {
+                       ett_netlink_hdr_flags, netlink_header_get_flags, encoding);
+               proto_tree_add_bitmask(fh_hdr, tvb, offset, hfi_netlink_hdr_flags.id,
+                       ett_netlink_hdr_flags, netlink_header_new_flags, encoding);
+       } else {
                proto_tree_add_bitmask(fh_hdr, tvb, offset, hfi_netlink_hdr_flags.id,
-                       ett_netlink_hdr_flags, netlink_header_new_flags, ENC_BIG_ENDIAN);
+                       ett_netlink_hdr_flags, netlink_header_standard_flags, encoding);
        }
 
        offset += 2;