Initial support for Generic Netlink (genl) dissection

For consistency with other netlink dissectors, the file is named
"netlink-generic", but the short protocol name is "genl" for brevity.

Ping-Bug: 13561
Change-Id: I6f94454f8366467fd833c3e57364c515aee9e86f
Reviewed-on: https://code.wireshark.org/review/20875
Petri-Dish: Michael Mann <mmann78@netscape.net>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Michael Mann <mmann78@netscape.net>

5 files changed, 562 insertions, 0 deletions

diff --git a/docbook/release-notes.asciidoc b/docbook/release-notes.asciidoc
index 0ecb0f59de..d0617fc73d 100644
--- a/docbook/release-notes.asciidoc
+++ b/docbook/release-notes.asciidoc
@@ -62,6 +62,7 @@ CAN FD
 Ericsson A-bis P-GSL
 Ericsson A-bis TFP (Traffic Forwarding Protocol)
 Fc00/cjdns Protocol
+Generic Netlink (genl)
 GSM Osmux
 Health Level 7 (HL7)
 High-speed SECS message service (HSMS)
diff --git a/epan/dissectors/CMakeLists.txt b/epan/dissectors/CMakeLists.txt
index 24167e7314..b9b62ef06b 100644
--- a/epan/dissectors/CMakeLists.txt
+++ b/epan/dissectors/CMakeLists.txt
@@ -961,6 +961,7 @@ set(DISSECTOR_SRC
 	packet-netbios.c
 	packet-netdump.c
 	packet-netflow.c
+	packet-netlink-generic.c
 	packet-netlink-netfilter.c
 	packet-netlink-route.c
 	packet-netlink-sock_diag.c
diff --git a/epan/dissectors/Makefile.am b/epan/dissectors/Makefile.am
index 503b061e04..996194367e 100644
--- a/epan/dissectors/Makefile.am
+++ b/epan/dissectors/Makefile.am
@@ -983,6 +983,7 @@ DISSECTOR_SRC = \
 	packet-netbios.c	\
 	packet-netdump.c	\
 	packet-netflow.c	\
+	packet-netlink-generic.c	\
 	packet-netlink-netfilter.c	\
 	packet-netlink-route.c	\
 	packet-netlink-sock_diag.c	\
diff --git a/epan/dissectors/packet-netlink-generic.c b/epan/dissectors/packet-netlink-generic.c
new file mode 100644
index 0000000000..8caa8b18a7
--- /dev/null
+++ b/epan/dissectors/packet-netlink-generic.c
@@ -0,0 +1,546 @@
+/* packet-netlink-generic.c
+ * Dissector for Linux Generic Netlink.
+ *
+ * Copyright (c) 2017, Peter Wu <peter@lekensteyn.nl>
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 1998 Gerald Combs
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#define NEW_PROTO_TREE_API
+
+#include "config.h"
+
+#include <epan/packet.h>
+#include "packet-netlink.h"
+
+/*
+ * Documentation:
+ * https://wiki.linuxfoundation.org/networking/generic_netlink_howto#message-format
+ * include/uapi/linux/netlink.h
+ * include/uapi/linux/genetlink.h
+ *
+ * For the meaning of fields in genlmsghdr, see genlmsg_put in
+ * net/netlink/genetlink.c, note that it has no user-specific message header
+ * (genl_ctrl.hdr_size==0).
+ */
+
+void proto_register_netlink_generic(void);
+void proto_reg_handoff_netlink_generic(void);
+
+typedef struct {
+	struct packet_netlink_data *data;
+	int             encoding; /* copy of data->encoding */
+
+	/* Values parsed from the attributes (only valid in this packet). */
+	guint16         family_id;
+	const guint8   *family_name;
+} genl_ctrl_info_t;
+
+/* from include/uapi/linux/genetlink.h */
+enum {
+	WS_CTRL_CMD_UNSPEC,
+	WS_CTRL_CMD_NEWFAMILY,
+	WS_CTRL_CMD_DELFAMILY,
+	WS_CTRL_CMD_GETFAMILY,
+	WS_CTRL_CMD_NEWOPS,
+	WS_CTRL_CMD_DELOPS,
+	WS_CTRL_CMD_GETOPS,
+	WS_CTRL_CMD_NEWMCAST_GRP,
+	WS_CTRL_CMD_DELMCAST_GRP,
+	WS_CTRL_CMD_GETMCAST_GRP,
+};
+enum ws_genl_ctrl_attr {
+	WS_CTRL_ATTR_UNSPEC,
+	WS_CTRL_ATTR_FAMILY_ID,
+	WS_CTRL_ATTR_FAMILY_NAME,
+	WS_CTRL_ATTR_VERSION,
+	WS_CTRL_ATTR_HDRSIZE,
+	WS_CTRL_ATTR_MAXATTR,
+	WS_CTRL_ATTR_OPS,
+	WS_CTRL_ATTR_MCAST_GROUPS,
+};
+
+enum ws_genl_ctrl_op_attr {
+	WS_CTRL_ATTR_OP_UNSPEC,
+	WS_CTRL_ATTR_OP_ID,
+	WS_CTRL_ATTR_OP_FLAGS,
+};
+
+enum ws_genl_ctrl_group_attr {
+	WS_CTRL_ATTR_MCAST_GRP_UNSPEC,
+	WS_CTRL_ATTR_MCAST_GRP_NAME,
+	WS_CTRL_ATTR_MCAST_GRP_ID,
+};
+
+#define WS_GENL_ID_CTRL 0x10
+#define GENL_CTRL_NAME "nlctrl"
+
+static const value_string genl_ctrl_cmds[] = {
+	{ WS_CTRL_CMD_UNSPEC,           "CTRL_CMD_UNSPEC" },
+	{ WS_CTRL_CMD_NEWFAMILY,        "CTRL_CMD_NEWFAMILY" },
+	{ WS_CTRL_CMD_DELFAMILY,        "CTRL_CMD_DELFAMILY" },
+	{ WS_CTRL_CMD_GETFAMILY,        "CTRL_CMD_GETFAMILY" },
+	{ WS_CTRL_CMD_NEWOPS,           "CTRL_CMD_NEWOPS" },
+	{ WS_CTRL_CMD_DELOPS,           "CTRL_CMD_DELOPS" },
+	{ WS_CTRL_CMD_GETOPS,           "CTRL_CMD_GETOPS" },
+	{ WS_CTRL_CMD_NEWMCAST_GRP,     "CTRL_CMD_NEWMCAST_GRP" },
+	{ WS_CTRL_CMD_DELMCAST_GRP,     "CTRL_CMD_DELMCAST_GRP" },
+	{ WS_CTRL_CMD_GETMCAST_GRP,     "CTRL_CMD_GETMCAST_GRP" },
+	{ 0, NULL }
+};
+
+static const value_string genl_ctrl_attr_vals[] = {
+	{ WS_CTRL_ATTR_UNSPEC,          "CTRL_ATTR_UNSPEC" },
+	{ WS_CTRL_ATTR_FAMILY_ID,       "CTRL_ATTR_FAMILY_ID" },
+	{ WS_CTRL_ATTR_FAMILY_NAME,     "CTRL_ATTR_FAMILY_NAME" },
+	{ WS_CTRL_ATTR_VERSION,         "CTRL_ATTR_VERSION" },
+	{ WS_CTRL_ATTR_HDRSIZE,         "CTRL_ATTR_HDRSIZE" },
+	{ WS_CTRL_ATTR_MAXATTR,         "CTRL_ATTR_MAXATTR" },
+	{ WS_CTRL_ATTR_OPS,             "CTRL_ATTR_OPS" },
+	{ WS_CTRL_ATTR_MCAST_GROUPS,    "CTRL_ATTR_MCAST_GROUPS" },
+	{ 0, NULL }
+};
+
+static const value_string genl_ctrl_op_attr_vals[] = {
+	{ WS_CTRL_ATTR_OP_UNSPEC,       "CTRL_ATTR_OP_UNSPEC" },
+	{ WS_CTRL_ATTR_OP_ID,           "CTRL_ATTR_OP_ID" },
+	{ WS_CTRL_ATTR_OP_FLAGS,        "CTRL_ATTR_OP_FLAGS" },
+	{ 0, NULL }
+};
+
+static const value_string genl_ctrl_group_attr_vals[] = {
+	{ WS_CTRL_ATTR_MCAST_GRP_UNSPEC, "CTRL_ATTR_MCAST_GRP_UNSPEC" },
+	{ WS_CTRL_ATTR_MCAST_GRP_NAME,  "CTRL_ATTR_MCAST_GRP_NAME" },
+	{ WS_CTRL_ATTR_MCAST_GRP_ID,    "CTRL_ATTR_MCAST_GRP_ID" },
+	{ 0, NULL }
+};
+
+static int proto_netlink_generic;
+
+static dissector_handle_t netlink_generic;
+static dissector_handle_t netlink_generic_ctrl;
+static dissector_table_t genl_dissector_table;
+
+static header_field_info *hfi_netlink_generic = NULL;
+
+#define NETLINK_GENERIC_HFI_INIT HFI_INIT(proto_netlink_generic)
+
+static gint ett_netlink_generic = -1;
+static gint ett_genl_ctrl_attr = -1;
+static gint ett_genl_ctrl_ops = -1;
+static gint ett_genl_ctrl_ops_attr = -1;
+static gint ett_genl_ctrl_op_flags = -1;
+static gint ett_genl_ctrl_groups = -1;
+static gint ett_genl_ctrl_groups_attr = -1;
+static gint ett_genl_nested_attr = -1;
+
+/*
+ * Maps family IDs (integers) to family names (strings) within a capture file.
+ */
+static wmem_map_t *genl_family_map;
+
+
+static header_field_info hfi_genl_ctrl_op_id NETLINK_GENERIC_HFI_INIT =
+	{ "Operation ID", "genl.ctrl.op_id", FT_UINT32, BASE_DEC,
+	  NULL, 0x00, NULL, HFILL };
+
+static header_field_info hfi_genl_ctrl_op_flags NETLINK_GENERIC_HFI_INIT =
+	{ "Operation Flags", "genl.ctrl.op_flags", FT_UINT32, BASE_HEX,
+	  NULL, 0x00, NULL, HFILL };
+
+static header_field_info hfi_genl_ctrl_op_flags_admin_perm NETLINK_GENERIC_HFI_INIT =
+	{ "GENL_ADMIN_PERM", "genl.ctrl.op_flags.admin_perm", FT_BOOLEAN, 32,
+	  NULL, 0x01, NULL, HFILL };
+
+static header_field_info hfi_genl_ctrl_op_flags_cmd_cap_do NETLINK_GENERIC_HFI_INIT =
+	{ "GENL_CMD_CAP_DO", "genl.ctrl.op_flags.cmd_cap_do", FT_BOOLEAN, 32,
+	  NULL, 0x02, NULL, HFILL };
+
+static header_field_info hfi_genl_ctrl_op_flags_cmd_cap_dump NETLINK_GENERIC_HFI_INIT =
+	{ "GENL_CMD_CAP_DUMP", "genl.ctrl.op_flags.cmd_cap_dump", FT_BOOLEAN, 32,
+	  NULL, 0x04, NULL, HFILL };
+
+static header_field_info hfi_genl_ctrl_op_flags_cmd_cap_haspol NETLINK_GENERIC_HFI_INIT =
+	{ "GENL_CMD_CAP_HASPOL", "genl.ctrl.op_flags.cmd_cap_haspol", FT_BOOLEAN, 32,
+	  NULL, 0x08, NULL, HFILL };
+
+static header_field_info hfi_genl_ctrl_op_flags_uns_admin_perm NETLINK_GENERIC_HFI_INIT =
+	{ "GENL_UNS_ADMIN_PERM", "genl.ctrl.op_flags.uns_admin_perm", FT_BOOLEAN, 32,
+	  NULL, 0x10, NULL, HFILL };
+
+static const int *genl_ctrl_op_flags_fields[] = {
+	&hfi_genl_ctrl_op_flags_admin_perm.id,
+	&hfi_genl_ctrl_op_flags_cmd_cap_do.id,
+	&hfi_genl_ctrl_op_flags_cmd_cap_dump.id,
+	&hfi_genl_ctrl_op_flags_cmd_cap_haspol.id,
+	&hfi_genl_ctrl_op_flags_uns_admin_perm.id,
+	NULL
+};
+
+static int
+dissect_genl_ctrl_ops_attrs(tvbuff_t *tvb, void *data, proto_tree *tree, int nla_type, int offset, int len)
+{
+	enum ws_genl_ctrl_op_attr type = (enum ws_genl_ctrl_op_attr) nla_type;
+	genl_ctrl_info_t *info = (genl_ctrl_info_t *) data;
+	proto_tree *ptree = proto_tree_get_parent_tree(tree);
+	guint32 value;
+
+	switch (type) {
+	case WS_CTRL_ATTR_OP_UNSPEC:
+		break;
+	case WS_CTRL_ATTR_OP_ID:
+		if (len == 4) {
+			proto_tree_add_item_ret_uint(tree, hfi_genl_ctrl_op_id.id, tvb, offset, 4, info->encoding, &value);
+			proto_item_append_text(tree, ": %u", value);
+			proto_item_append_text(ptree, ", id=%u", value);
+			offset += 4;
+		}
+		break;
+	case WS_CTRL_ATTR_OP_FLAGS:
+		if (len == 4) {
+			guint64 op_flags;
+			/* XXX it would be nice if the flag names are appended to the tree */
+			proto_tree_add_bitmask_with_flags_ret_uint64(tree, tvb, offset, hfi_genl_ctrl_op_flags.id, ett_genl_ctrl_op_flags, genl_ctrl_op_flags_fields, info->encoding, BMT_NO_FALSE, &op_flags);
+			proto_item_append_text(tree, ": 0x%08x", (guint32)op_flags);
+			proto_item_append_text(ptree, ", flags=0x%08x", (guint32)op_flags);
+			offset += 4;
+		}
+		break;
+	}
+
+	return offset;
+}
+
+
+static header_field_info hfi_genl_ctrl_group_name NETLINK_GENERIC_HFI_INIT =
+	{ "Group Name", "genl.ctrl.group_name", FT_STRINGZ, STR_ASCII,
+	  NULL, 0x00, NULL, HFILL };
+
+static header_field_info hfi_genl_ctrl_group_id NETLINK_GENERIC_HFI_INIT =
+	{ "Group ID", "genl.ctrl.group_id", FT_UINT32, BASE_HEX,
+	  NULL, 0x00, NULL, HFILL };
+
+static int
+dissect_genl_ctrl_groups_attrs(tvbuff_t *tvb, void *data, proto_tree *tree, int nla_type, int offset, int len)
+{
+	enum ws_genl_ctrl_group_attr type = (enum ws_genl_ctrl_group_attr) nla_type;
+	genl_ctrl_info_t *info = (genl_ctrl_info_t *) data;
+	proto_tree *ptree = proto_tree_get_parent_tree(tree);
+	guint32 value;
+	const guint8 *strval;
+
+	switch (type) {
+	case WS_CTRL_ATTR_MCAST_GRP_UNSPEC:
+		break;
+	case WS_CTRL_ATTR_MCAST_GRP_NAME:
+		proto_tree_add_item_ret_string(tree, hfi_genl_ctrl_group_name.id, tvb, offset, len, ENC_ASCII, wmem_packet_scope(), &strval);
+		proto_item_append_text(tree, ": %s", strval);
+		proto_item_append_text(ptree, ", name=%s", strval);
+		offset += len;
+		break;
+	case WS_CTRL_ATTR_MCAST_GRP_ID:
+		if (len == 4) {
+			proto_tree_add_item_ret_uint(tree, hfi_genl_ctrl_group_id.id, tvb, offset, 4, info->encoding, &value);
+			proto_item_append_text(tree, ": %u", value);
+			proto_item_append_text(ptree, ", id=%u", value);
+			offset += 4;
+		}
+		break;
+	}
+
+	return offset;
+}
+
+
+static header_field_info hfi_genl_ctrl_family_id NETLINK_GENERIC_HFI_INIT =
+	{ "Family ID", "genl.ctrl.family_id", FT_UINT16, BASE_HEX,
+	  NULL, 0x00, NULL, HFILL };
+
+static header_field_info hfi_genl_ctrl_family_name NETLINK_GENERIC_HFI_INIT =
+	{ "Family Name", "genl.ctrl.family_name", FT_STRINGZ, STR_ASCII,
+	  NULL, 0x00, NULL, HFILL };
+
+static header_field_info hfi_genl_ctrl_version NETLINK_GENERIC_HFI_INIT =
+	{ "Version", "genl.ctrl.version", FT_UINT32, BASE_DEC,
+	  NULL, 0x00, "Family-specific version number", HFILL };
+
+static header_field_info hfi_genl_ctrl_hdrsize NETLINK_GENERIC_HFI_INIT =
+	{ "Header Size", "genl.ctrl.hdrsize", FT_UINT32, BASE_DEC,
+	  NULL, 0x00, "Size of family-specific header", HFILL };
+
+static header_field_info hfi_genl_ctrl_maxattr NETLINK_GENERIC_HFI_INIT =
+	{ "Maximum Attributes", "genl.ctrl.maxattr", FT_UINT32, BASE_DEC,
+	  NULL, 0x00, "Maximum number of attributes", HFILL };
+
+static header_field_info hfi_genl_ctrl_ops_attr NETLINK_GENERIC_HFI_INIT =
+	{ "Type", "genl.ctrl.ops_attr", FT_UINT16, BASE_DEC,
+	  VALS(genl_ctrl_op_attr_vals), NLA_TYPE_MASK, NULL, HFILL };
+
+static header_field_info hfi_genl_ctrl_groups_attr NETLINK_GENERIC_HFI_INIT =
+	{ "Type", "genl.ctrl.groups_attr", FT_UINT16, BASE_DEC,
+	  VALS(genl_ctrl_group_attr_vals), NLA_TYPE_MASK, NULL, HFILL };
+
+static int
+dissect_genl_ctrl_attrs(tvbuff_t *tvb, void *data, proto_tree *tree, int nla_type, int offset, int len)
+{
+	enum ws_genl_ctrl_attr type = (enum ws_genl_ctrl_attr) nla_type;
+	genl_ctrl_info_t *info = (genl_ctrl_info_t *) data;
+	guint32 value;
+
+	switch (type) {
+	case WS_CTRL_CMD_UNSPEC:
+		break;
+	case WS_CTRL_ATTR_FAMILY_ID:
+		if (len == 2) {
+			proto_tree_add_item_ret_uint(tree, hfi_genl_ctrl_family_id.id, tvb, offset, 2, info->encoding, &value);
+			proto_item_append_text(tree, ": %#x", value);
+			info->family_id = value;
+			offset += 2;
+		}
+		break;
+	case WS_CTRL_ATTR_FAMILY_NAME:
+		proto_tree_add_item_ret_string(tree, hfi_genl_ctrl_family_name.id, tvb, offset, len, ENC_ASCII, wmem_packet_scope(), &info->family_name);
+		proto_item_append_text(tree, ": %s", info->family_name);
+		offset += len;
+		break;
+	case WS_CTRL_ATTR_VERSION:
+		if (len == 4) {
+			proto_tree_add_item_ret_uint(tree, hfi_genl_ctrl_version.id, tvb, offset, 4, info->encoding, &value);
+			proto_item_append_text(tree, ": %u", value);
+			offset += 4;
+		}
+		break;
+	case WS_CTRL_ATTR_HDRSIZE:
+		if (len == 4) {
+			proto_tree_add_item_ret_uint(tree, hfi_genl_ctrl_hdrsize.id, tvb, offset, 4, info->encoding, &value);
+			proto_item_append_text(tree, ": %u", value);
+			offset += 4;
+		}
+		break;
+	case WS_CTRL_ATTR_MAXATTR:
+		if (len == 4) {
+			proto_tree_add_item_ret_uint(tree, hfi_genl_ctrl_maxattr.id, tvb, offset, 4, info->encoding, &value);
+			proto_item_append_text(tree, ": %u", value);
+			offset += 4;
+		}
+		break;
+	case WS_CTRL_ATTR_OPS:
+		offset = dissect_netlink_attributes_array(tvb, &hfi_genl_ctrl_ops_attr, ett_genl_ctrl_ops, ett_genl_ctrl_ops_attr, info, info->data, tree, offset, len, dissect_genl_ctrl_ops_attrs);
+		break;
+	case WS_CTRL_ATTR_MCAST_GROUPS:
+		offset = dissect_netlink_attributes_array(tvb, &hfi_genl_ctrl_groups_attr, ett_genl_ctrl_groups, ett_genl_ctrl_groups_attr, info, info->data, tree, offset, len, dissect_genl_ctrl_groups_attrs);
+		break;
+	}
+
+	return offset;
+}
+
+static header_field_info hfi_genl_ctrl_attr NETLINK_GENERIC_HFI_INIT =
+	{ "Type", "genl.ctrl_attr", FT_UINT16, BASE_DEC,
+	  VALS(genl_ctrl_attr_vals), NLA_TYPE_MASK, NULL, HFILL };
+
+static int
+dissect_genl_ctrl(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree, void *data)
+{
+	genl_info_t *genl_info = (genl_info_t *) data;
+	genl_ctrl_info_t info;
+
+	if (!genl_info) {
+		return 0;
+	}
+
+	info.data = genl_info->data;
+	info.encoding = genl_info->encoding;
+	info.family_id = 0;
+	info.family_name = NULL;
+
+	proto_item_append_text(genl_info->cmd_pi, " (%s)",
+			val_to_str_const(genl_info->cmd, genl_ctrl_cmds, "Unknown"));
+	dissect_netlink_attributes(tvb, &hfi_genl_ctrl_attr, ett_genl_ctrl_attr, &info, info.data, tree, 0, -1, dissect_genl_ctrl_attrs);
+
+	/*
+	 * Remember association of dynamic ID with the family name such that
+	 * future packets can be linked to a protocol.
+	 * Do not allow overwriting our control protocol.
+	 */
+	if (info.family_id && info.family_id != WS_GENL_ID_CTRL && info.family_name) {
+		wmem_map_insert(genl_family_map, GUINT_TO_POINTER(info.family_id), wmem_strdup(wmem_file_scope(), info.family_name));
+	}
+
+	return tvb_captured_length(tvb);
+}
+
+
+static header_field_info hfi_genl_family_id NETLINK_GENERIC_HFI_INIT =
+	{ "Family ID", "genl.family_id", FT_UINT8, BASE_HEX,
+	  NULL, 0x00, NULL, HFILL };
+
+static header_field_info hfi_genl_cmd NETLINK_GENERIC_HFI_INIT =
+	{ "Command", "genl.cmd", FT_UINT8, BASE_DEC,
+	  NULL, 0x00, "Generic Netlink command", HFILL };
+
+static header_field_info hfi_genl_version NETLINK_GENERIC_HFI_INIT =
+	{ "Family Version", "genl.version", FT_UINT8, BASE_DEC,
+	  NULL, 0x00, "Family-specfic version", HFILL };
+
+static header_field_info hfi_genl_reserved NETLINK_GENERIC_HFI_INIT =
+	{ "Reserved", "genl.reserved", FT_NONE, BASE_NONE,
+	  NULL, 0x00, NULL, HFILL };
+
+static int
+dissect_netlink_generic(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *_data)
+{
+	struct packet_netlink_data *data = (struct packet_netlink_data *)_data;
+	genl_info_t info;
+	proto_tree *nlmsg_tree;
+	proto_item *pi, *pi_type;
+	guint32 cmd;
+	const char *family_name;
+	int offset = 0;
+
+	DISSECTOR_ASSERT(data && data->magic == PACKET_NETLINK_MAGIC);
+
+	col_set_str(pinfo->cinfo, COL_PROTOCOL, "Netlink generic");
+	col_clear(pinfo->cinfo, COL_INFO);
+
+	pi = proto_tree_add_item(tree, proto_registrar_get_nth(proto_netlink_generic), tvb, 0, -1, ENC_NA);
+	nlmsg_tree = proto_item_add_subtree(pi, ett_netlink_generic);
+
+	/* Netlink message header (nlmsghdr) */
+	offset = dissect_netlink_header(tvb, nlmsg_tree, offset, data->encoding, &hfi_genl_family_id, &pi_type);
+	family_name = (const char *)wmem_map_lookup(genl_family_map, GUINT_TO_POINTER(data->type));
+	proto_item_append_text(pi_type, " (%s)", family_name ? family_name : "Unknown");
+
+	/* Generic Netlink message header (genlmsghdr)  */
+	info.data = data;
+	info.encoding = data->encoding;
+	info.cmd_pi = proto_tree_add_item_ret_uint(nlmsg_tree, hfi_genl_cmd.id, tvb, offset, 1, ENC_NA, &cmd);
+	info.cmd = cmd;
+	offset++;
+	proto_tree_add_item(nlmsg_tree, &hfi_genl_version, tvb, offset, 1, ENC_NA);
+	offset++;
+	proto_tree_add_item(nlmsg_tree, &hfi_genl_reserved, tvb, offset, 2, ENC_NA);
+	offset += 2;
+
+	/* Optional user-specific message header and optional message payload. */
+	if (tvb_reported_length_remaining(tvb, offset)) {
+		tvbuff_t *next_tvb = tvb_new_subset_remaining(tvb, offset);
+		if (family_name) {
+			int ret;
+			/* XXX should subdissectors add to the top-level tree? */
+			ret = dissector_try_string(genl_dissector_table, family_name, next_tvb, pinfo, nlmsg_tree, &info);
+			if (ret) {
+				return ret;
+			}
+		}
+
+		/* fallback if no subdissector was found. */
+		call_data_dissector(next_tvb, pinfo, tree);
+	}
+
+	return offset;
+}
+
+static void
+genl_init(void)
+{
+	/* Add fixed family entry (0x10 maps to "nlctrl"). */
+	wmem_map_insert(genl_family_map, GUINT_TO_POINTER(WS_GENL_ID_CTRL), GENL_CTRL_NAME);
+}
+
+void
+proto_register_netlink_generic(void)
+{
+#ifndef HAVE_HFI_SECTION_INIT
+	static header_field_info *hfi[] = {
+		&hfi_genl_family_id,
+		&hfi_genl_cmd,
+		&hfi_genl_version,
+		&hfi_genl_reserved,
+		&hfi_genl_ctrl_attr,
+		/* Controller */
+		&hfi_genl_ctrl_family_id,
+		&hfi_genl_ctrl_family_name,
+		&hfi_genl_ctrl_version,
+		&hfi_genl_ctrl_hdrsize,
+		&hfi_genl_ctrl_maxattr,
+		&hfi_genl_ctrl_ops_attr,
+		&hfi_genl_ctrl_groups_attr,
+		&hfi_genl_ctrl_op_id,
+		&hfi_genl_ctrl_op_flags,
+		&hfi_genl_ctrl_op_flags_admin_perm,
+		&hfi_genl_ctrl_op_flags_cmd_cap_do,
+		&hfi_genl_ctrl_op_flags_cmd_cap_dump,
+		&hfi_genl_ctrl_op_flags_cmd_cap_haspol,
+		&hfi_genl_ctrl_op_flags_uns_admin_perm,
+		&hfi_genl_ctrl_group_name,
+		&hfi_genl_ctrl_group_id,
+	};
+#endif
+
+	static gint *ett[] = {
+		&ett_netlink_generic,
+		&ett_genl_ctrl_attr,
+		&ett_genl_ctrl_ops,
+		&ett_genl_ctrl_ops_attr,
+		&ett_genl_ctrl_op_flags,
+		&ett_genl_ctrl_groups,
+		&ett_genl_ctrl_groups_attr,
+		&ett_genl_nested_attr,
+	};
+
+	proto_netlink_generic = proto_register_protocol("Linux Generic Netlink protocol", "genl", "genl");
+	hfi_netlink_generic = proto_registrar_get_nth(proto_netlink_generic);
+
+	proto_register_fields(proto_netlink_generic, hfi, array_length(hfi));
+	proto_register_subtree_array(ett, array_length(ett));
+
+	netlink_generic = create_dissector_handle(dissect_netlink_generic, proto_netlink_generic);
+	netlink_generic_ctrl = create_dissector_handle(dissect_genl_ctrl, proto_netlink_generic);
+	genl_dissector_table = register_dissector_table(
+		"genl.family",
+		"Linux Generic Netlink family name",
+		proto_netlink_generic, FT_STRING,
+		BASE_NONE
+	);
+
+	genl_family_map = wmem_map_new_autoreset(wmem_epan_scope(), wmem_file_scope(), g_direct_hash, g_direct_equal);
+
+	register_init_routine(genl_init);
+}
+
+void
+proto_reg_handoff_netlink_generic(void)
+{
+	dissector_add_string("genl.family", GENL_CTRL_NAME, netlink_generic_ctrl);
+	dissector_add_uint("netlink.protocol", WS_NETLINK_GENERIC, netlink_generic);
+}
+
+/*
+ * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
+ *
+ * Local variables:
+ * c-basic-offset: 8
+ * tab-width: 8
+ * indent-tabs-mode: t
+ * End:
+ *
+ * vi: set shiftwidth=8 tabstop=8 noexpandtab:
+ * :indentSize=8:tabSize=8:noTabs=false:
+ */
diff --git a/epan/dissectors/packet-netlink.h b/epan/dissectors/packet-netlink.h
index fd379fe507..12b872e2e7 100644
--- a/epan/dissectors/packet-netlink.h
+++ b/epan/dissectors/packet-netlink.h
@@ -127,4 +127,17 @@ int dissect_netlink_attributes_array(tvbuff_t *tvb, header_field_info *hfi_type,
 #define NLA_F_NET_BYTEORDER     0x4000
 #define NLA_TYPE_MASK           0x3fff
 
+
+/*
+ * Format of the data that is passed to "genl.family" dissectors.
+ */
+typedef struct {
+	struct packet_netlink_data *data;
+	int             encoding; /* copy of data->encoding */
+
+	/* fields from genlmsghdr */
+	guint8 	        cmd; /* Command number */
+	proto_item     *cmd_pi; /* Field for command, for appending protocol-specific name. */
+} genl_info_t;
+
 #endif /* __PACKET_NETLINK_H__ */