Netlink: remove encoding copies and, by extension, nl_data copies

The underlying netlink dissector sets up a data structure to help maintain
information about the netlink packet. This contains the encoding information
as determined for this packet. Use this value in place of the copy that
every netlink dissector makes in its private data structure.
As a consequence the encoding field can be removed from these private data
structures. Since the encoding field is now directly available from the
data structure setup by the underlying netlink dissector, the private data
structures also do not need to keep a pointer to this underlying netlink
dissector data structure.
This change replaces the use of the local copy of encoding with the
original one. This change, by extension, also removes the encoding field and
the pointer to the underlying netlink dissector data structure as these are
no longer needed. The exception is the generic netlink dissector, which
implements the dynamic netlink famiily subdissector table.

Change-Id: Ida0065379c19ae68caf6d87860828b48766c1998
Reviewed-on: https://code.wireshark.org/review/35698
Reviewed-by: Jaap Keuter <jaap.keuter@xs4all.nl>
Petri-Dish: Jaap Keuter <jaap.keuter@xs4all.nl>
Tested-by: Petri Dish Buildbot
Reviewed-by: Anders Broman <a.broman58@gmail.com>

1 files changed, 48 insertions, 54 deletions

diff --git a/epan/dissectors/packet-netlink-route.c b/epan/dissectors/packet-netlink-route.c
index ac463ac5dd..9c9d5695c7 100644
--- a/epan/dissectors/packet-netlink-route.c
+++ b/epan/dissectors/packet-netlink-route.c
@@ -25,9 +25,6 @@ void proto_reg_handoff_netlink_route(void);
 
 struct netlink_route_info {
 	packet_info *pinfo;
-	struct packet_netlink_data *nl_data;
-
-	int encoding; /* copy of nl_data->encoding */
 	gboolean legacy;
 };
 
@@ -438,12 +435,12 @@ static header_field_info hfi_netlink_route_ifi_change NETLINK_ROUTE_HFI_INIT =
 
 
 static int
-dissect_netlink_route_ifinfomsg(tvbuff_t *tvb, struct netlink_route_info *info, struct packet_netlink_data *nl_data _U_, proto_tree *tree, int offset)
+dissect_netlink_route_ifinfomsg(tvbuff_t *tvb, struct netlink_route_info *info, struct packet_netlink_data *nl_data, proto_tree *tree, int offset)
 {
 	proto_item *ti;
 	proto_tree *if_flags_tree;
 
-	proto_tree_add_item(tree, &hfi_netlink_route_ifi_family, tvb, offset, 1, info->encoding);
+	proto_tree_add_item(tree, &hfi_netlink_route_ifi_family, tvb, offset, 1, nl_data->encoding);
 	offset += 1;
 
 	if (info->legacy)
@@ -452,23 +449,23 @@ dissect_netlink_route_ifinfomsg(tvbuff_t *tvb, struct netlink_route_info *info,
 	/* XXX padding, check if 0 */
 	offset += 1;
 
-	proto_tree_add_item(tree, &hfi_netlink_route_ifi_type, tvb, offset, 2, info->encoding);
+	proto_tree_add_item(tree, &hfi_netlink_route_ifi_type, tvb, offset, 2, nl_data->encoding);
 	offset += 2;
 
-	proto_tree_add_item(tree, &hfi_netlink_route_ifi_index, tvb, offset, 4, info->encoding);
+	proto_tree_add_item(tree, &hfi_netlink_route_ifi_index, tvb, offset, 4, nl_data->encoding);
 	offset += 4;
 
-	ti = proto_tree_add_item(tree, &hfi_netlink_route_ifi_flags, tvb, offset, 4, info->encoding);
+	ti = proto_tree_add_item(tree, &hfi_netlink_route_ifi_flags, tvb, offset, 4, nl_data->encoding);
 	if_flags_tree = proto_item_add_subtree(ti, ett_netlink_route_if_flags);
 
 	if (if_flags_tree) {
-		proto_tree_add_item(if_flags_tree, &hfi_netlink_route_ifi_flags_iff_up, tvb, offset, 4, info->encoding);
-		proto_tree_add_item(if_flags_tree, &hfi_netlink_route_ifi_flags_iff_broadcast, tvb, offset, 4, info->encoding);
+		proto_tree_add_item(if_flags_tree, &hfi_netlink_route_ifi_flags_iff_up, tvb, offset, 4, nl_data->encoding);
+		proto_tree_add_item(if_flags_tree, &hfi_netlink_route_ifi_flags_iff_broadcast, tvb, offset, 4, nl_data->encoding);
 		/* XXX */
 	}
 	offset += 4;
 
-	proto_tree_add_item(tree, &hfi_netlink_route_ifi_change, tvb, offset, 4, info->encoding);
+	proto_tree_add_item(tree, &hfi_netlink_route_ifi_change, tvb, offset, 4, nl_data->encoding);
 	offset += 4;
 
 	return offset;
@@ -768,26 +765,27 @@ static header_field_info* linkstat_txerr_hfis[] = {
 };
 
 static int
-dissect_netlink_route_ifla_linkstats(tvbuff_t *tvb, struct netlink_route_info *info, struct packet_netlink_data *nl_data _U_, proto_tree *tree, int offset, int byte_size) {
+dissect_netlink_route_ifla_linkstats(tvbuff_t *tvb, struct netlink_route_info *info _U_, struct packet_netlink_data *nl_data, proto_tree *tree, int offset, int byte_size)
+{
 	proto_tree* rxerr_subtree;
 	const gint rxerr_hfis_len = (sizeof(linkstat_rxerr_hfis) / sizeof(header_field_info*));
 	proto_tree* txerr_subtree;
 	const gint txerr_hfis_len = (sizeof(linkstat_txerr_hfis) / sizeof(header_field_info*));
 
 	for (size_t i = 0; i < (sizeof(linkstat_root_hfis) / sizeof(header_field_info*)); i++) {
-		proto_tree_add_item(tree, linkstat_root_hfis[i], tvb, offset, byte_size, info->encoding);
+		proto_tree_add_item(tree, linkstat_root_hfis[i], tvb, offset, byte_size, nl_data->encoding);
 		offset += byte_size;
 	}
 
 	rxerr_subtree = proto_tree_add_subtree(tree, tvb, offset, byte_size * rxerr_hfis_len, ett_netlink_route_attr_linkstats_rxerrs, NULL, "Rx errors");
 	for (gint i = 0; i < rxerr_hfis_len; i++) {
-		proto_tree_add_item(rxerr_subtree, linkstat_rxerr_hfis[i], tvb, offset, byte_size, info->encoding);
+		proto_tree_add_item(rxerr_subtree, linkstat_rxerr_hfis[i], tvb, offset, byte_size, nl_data->encoding);
 		offset += byte_size;
 	}
 
 	txerr_subtree = proto_tree_add_subtree(tree, tvb, offset, byte_size * txerr_hfis_len, ett_netlink_route_attr_linkstats_txerrs, NULL, "Tx errors");
 	for (gint i = 0; i < txerr_hfis_len; i++) {
-		proto_tree_add_item(txerr_subtree, linkstat_txerr_hfis[i], tvb, offset, byte_size, info->encoding);
+		proto_tree_add_item(txerr_subtree, linkstat_txerr_hfis[i], tvb, offset, byte_size, nl_data->encoding);
 		offset += byte_size;
 	}
 
@@ -809,54 +807,54 @@ dissect_netlink_route_ifla_attrs(tvbuff_t *tvb, void *data, struct packet_netlin
 			return 1;
 		case WS_IFLA_MTU:
 			proto_item_append_text(tree, ": %u", tvb_get_letohl(tvb, offset));
-			proto_tree_add_item(tree, &hfi_netlink_route_ifla_mtu, tvb, offset, len, info->encoding);
+			proto_tree_add_item(tree, &hfi_netlink_route_ifla_mtu, tvb, offset, len, nl_data->encoding);
 			return 1;
 		case WS_IFLA_TXQLEN:
 			proto_item_append_text(tree, ": %u", tvb_get_letohl(tvb, offset));
-			proto_tree_add_item(tree, &hfi_netlink_route_ifla_txqlen, tvb, offset, len, info->encoding);
+			proto_tree_add_item(tree, &hfi_netlink_route_ifla_txqlen, tvb, offset, len, nl_data->encoding);
 			return 1;
 		case WS_IFLA_OPERSTATE:
-			proto_tree_add_item(tree, &hfi_netlink_route_ifla_operstate, tvb, offset, len, info->encoding);
+			proto_tree_add_item(tree, &hfi_netlink_route_ifla_operstate, tvb, offset, len, nl_data->encoding);
 			return 1;
 		case WS_IFLA_PROMISCUITY:
 			proto_item_append_text(tree, ": %u", tvb_get_letohl(tvb, offset));
-			proto_tree_add_item(tree, &hfi_netlink_route_ifla_promiscuity, tvb, offset, len, info->encoding);
+			proto_tree_add_item(tree, &hfi_netlink_route_ifla_promiscuity, tvb, offset, len, nl_data->encoding);
 			return 1;
 		case WS_IFLA_NUM_TX_QUEUES:
 			proto_item_append_text(tree, ": %u", tvb_get_letohl(tvb, offset));
-			proto_tree_add_item(tree, &hfi_netlink_route_ifla_txqnum, tvb, offset, len, info->encoding);
+			proto_tree_add_item(tree, &hfi_netlink_route_ifla_txqnum, tvb, offset, len, nl_data->encoding);
 			return 1;
 		case WS_IFLA_NUM_RX_QUEUES:
 			proto_item_append_text(tree, ": %u", tvb_get_letohl(tvb, offset));
-			proto_tree_add_item(tree, &hfi_netlink_route_ifla_rxqnum, tvb, offset, len, info->encoding);
+			proto_tree_add_item(tree, &hfi_netlink_route_ifla_rxqnum, tvb, offset, len, nl_data->encoding);
 			return 1;
 		case WS_IFLA_GROUP:
 			proto_item_append_text(tree, ": %u", tvb_get_letohl(tvb, offset));
-			proto_tree_add_item(tree, &hfi_netlink_route_ifla_group, tvb, offset, len, info->encoding);
+			proto_tree_add_item(tree, &hfi_netlink_route_ifla_group, tvb, offset, len, nl_data->encoding);
 			return 1;
 		case WS_IFLA_GSO_MAX_SEGS:
 			proto_item_append_text(tree, ": %u", tvb_get_letohl(tvb, offset));
-			proto_tree_add_item(tree, &hfi_netlink_route_ifla_gso_maxsegs, tvb, offset, len, info->encoding);
+			proto_tree_add_item(tree, &hfi_netlink_route_ifla_gso_maxsegs, tvb, offset, len, nl_data->encoding);
 			return 1;
 		case WS_IFLA_GSO_MAX_SIZE:
 			proto_item_append_text(tree, ": %u", tvb_get_letohl(tvb, offset));
-			proto_tree_add_item(tree, &hfi_netlink_route_ifla_gso_maxsize, tvb, offset, len, info->encoding);
+			proto_tree_add_item(tree, &hfi_netlink_route_ifla_gso_maxsize, tvb, offset, len, nl_data->encoding);
 			return 1;
 		case WS_IFLA_CARRIER:
 			proto_item_append_text(tree, ": %u", tvb_get_letohl(tvb, offset));
-			proto_tree_add_item(tree, &hfi_netlink_route_ifla_carrier, tvb, offset, len, info->encoding);
+			proto_tree_add_item(tree, &hfi_netlink_route_ifla_carrier, tvb, offset, len, nl_data->encoding);
 			return 1;
 		case WS_IFLA_CARRIER_CHANGES:
 			proto_item_append_text(tree, ": %u", tvb_get_letohl(tvb, offset));
-			proto_tree_add_item(tree, &hfi_netlink_route_ifla_carrier_changes, tvb, offset, len, info->encoding);
+			proto_tree_add_item(tree, &hfi_netlink_route_ifla_carrier_changes, tvb, offset, len, nl_data->encoding);
 			return 1;
 		case WS_IFLA_ADDRESS:
 			proto_item_append_text(tree, ": %s", tvb_bytes_to_str_punct(wmem_packet_scope(), tvb, offset, len, ':'));
-			proto_tree_add_item(tree, &hfi_netlink_route_ifla_hwaddr, tvb, offset, len, info->encoding);
+			proto_tree_add_item(tree, &hfi_netlink_route_ifla_hwaddr, tvb, offset, len, nl_data->encoding);
 			return 1;
 		case WS_IFLA_BROADCAST:
 			proto_item_append_text(tree, ": %s", tvb_bytes_to_str_punct(wmem_packet_scope(), tvb, offset, len, ':'));
-			proto_tree_add_item(tree, &hfi_netlink_route_ifla_broadcast, tvb, offset, len, info->encoding);
+			proto_tree_add_item(tree, &hfi_netlink_route_ifla_broadcast, tvb, offset, len, nl_data->encoding);
 			return 1;
 		case WS_IFLA_STATS:
 			subtree = proto_tree_add_subtree(tree, tvb, offset, len, ett_netlink_route_attr_linkstats, NULL, "Statistics");
@@ -869,28 +867,28 @@ dissect_netlink_route_ifla_attrs(tvbuff_t *tvb, void *data, struct packet_netlin
 			proto_item_append_text(tree, ": %s", str);
 			return 1;
 		case WS_IFLA_MAP:
-			proto_tree_add_item(tree, &hfi_netlink_route_ifla_map_memstart, tvb, offset, 8, info->encoding);
-			proto_tree_add_item(tree, &hfi_netlink_route_ifla_map_memend, tvb, offset + 8, 8, info->encoding);
-			proto_tree_add_item(tree, &hfi_netlink_route_ifla_map_baseaddr, tvb, offset + 16, 8, info->encoding);
-			proto_tree_add_item(tree, &hfi_netlink_route_ifla_map_irq, tvb, offset + 24, 2, info->encoding);
-			proto_tree_add_item(tree, &hfi_netlink_route_ifla_map_dma, tvb, offset + 26, 1, info->encoding);
-			proto_tree_add_item(tree, &hfi_netlink_route_ifla_map_port, tvb, offset + 27, 1, info->encoding);
+			proto_tree_add_item(tree, &hfi_netlink_route_ifla_map_memstart, tvb, offset, 8, nl_data->encoding);
+			proto_tree_add_item(tree, &hfi_netlink_route_ifla_map_memend, tvb, offset + 8, 8, nl_data->encoding);
+			proto_tree_add_item(tree, &hfi_netlink_route_ifla_map_baseaddr, tvb, offset + 16, 8, nl_data->encoding);
+			proto_tree_add_item(tree, &hfi_netlink_route_ifla_map_irq, tvb, offset + 24, 2, nl_data->encoding);
+			proto_tree_add_item(tree, &hfi_netlink_route_ifla_map_dma, tvb, offset + 26, 1, nl_data->encoding);
+			proto_tree_add_item(tree, &hfi_netlink_route_ifla_map_port, tvb, offset + 27, 1, nl_data->encoding);
 			return 1;
 		case WS_IFLA_CARRIER_UP_COUNT:
 			proto_item_append_text(tree, ": %u", tvb_get_letohl(tvb, offset));
-			proto_tree_add_item(tree, &hfi_netlink_route_ifla_carrier_up_count, tvb, offset, len, info->encoding);
+			proto_tree_add_item(tree, &hfi_netlink_route_ifla_carrier_up_count, tvb, offset, len, nl_data->encoding);
 			return 1;
 		case WS_IFLA_CARRIER_DOWN_COUNT:
 			proto_item_append_text(tree, ": %u", tvb_get_letohl(tvb, offset));
-			proto_tree_add_item(tree, &hfi_netlink_route_ifla_carrier_down_count, tvb, offset, len, info->encoding);
+			proto_tree_add_item(tree, &hfi_netlink_route_ifla_carrier_down_count, tvb, offset, len, nl_data->encoding);
 			return 1;
 		case WS_IFLA_MIN_MTU:
 			proto_item_append_text(tree, ": %u", tvb_get_letohl(tvb, offset));
-			proto_tree_add_item(tree, &hfi_netlink_route_ifla_min_mtu, tvb, offset, len, info->encoding);
+			proto_tree_add_item(tree, &hfi_netlink_route_ifla_min_mtu, tvb, offset, len, nl_data->encoding);
 			return 1;
 		case WS_IFLA_MAX_MTU:
 			proto_item_append_text(tree, ": %u", tvb_get_letohl(tvb, offset));
-			proto_tree_add_item(tree, &hfi_netlink_route_ifla_max_mtu, tvb, offset, len, info->encoding);
+			proto_tree_add_item(tree, &hfi_netlink_route_ifla_max_mtu, tvb, offset, len, nl_data->encoding);
 			return 1;
 
 		default:
@@ -948,7 +946,7 @@ static header_field_info hfi_netlink_route_ifa_index NETLINK_ROUTE_HFI_INIT =
 	  NULL, 0x00, NULL, HFILL };
 
 static int
-dissect_netlink_route_ifaddrmsg(tvbuff_t *tvb, struct netlink_route_info *info, struct packet_netlink_data *nl_data _U_, proto_tree *tree, int offset)
+dissect_netlink_route_ifaddrmsg(tvbuff_t *tvb, struct netlink_route_info *info, struct packet_netlink_data *nl_data, proto_tree *tree, int offset)
 {
 	proto_tree_add_item(tree, &hfi_netlink_route_ifa_family,    tvb, offset, 1, ENC_NA);
 	offset += 1;
@@ -965,7 +963,7 @@ dissect_netlink_route_ifaddrmsg(tvbuff_t *tvb, struct netlink_route_info *info,
 	proto_tree_add_item(tree, &hfi_netlink_route_ifa_scope,	    tvb, offset, 1, ENC_NA);
 	offset += 1;
 
-	proto_tree_add_item(tree, &hfi_netlink_route_ifa_index,	    tvb, offset, 4, info->encoding);
+	proto_tree_add_item(tree, &hfi_netlink_route_ifa_index,	    tvb, offset, 4, nl_data->encoding);
 	offset += 4;
 
 	return offset;
@@ -1009,9 +1007,8 @@ static header_field_info hfi_netlink_route_ifa_addr4 NETLINK_ROUTE_HFI_INIT =
 	  NULL, 0x00, NULL, HFILL };
 
 static int
-dissect_netlink_route_ifa_attrs(tvbuff_t *tvb, void *data, struct packet_netlink_data *nl_data _U_, proto_tree *tree, int rta_type, int offset, int len)
+dissect_netlink_route_ifa_attrs(tvbuff_t *tvb, void *data _U_, struct packet_netlink_data *nl_data, proto_tree *tree, int rta_type, int offset, int len)
 {
-	struct netlink_route_info *info = (struct netlink_route_info *)data;
 	enum ws_ifa_attr_type type = (enum ws_ifa_attr_type) rta_type;
 	const guint8* str;
 
@@ -1022,7 +1019,7 @@ dissect_netlink_route_ifa_attrs(tvbuff_t *tvb, void *data, struct packet_netlink
 			return 1;
 
 		case WS_IFA_FLAGS:
-			proto_tree_add_item(tree, &hfi_netlink_route_ifa_flags32, tvb, offset, 4, info->encoding);
+			proto_tree_add_item(tree, &hfi_netlink_route_ifa_flags32, tvb, offset, 4, nl_data->encoding);
 			return 1;
 		case WS_IFA_ADDRESS:
 		case WS_IFA_LOCAL:
@@ -1130,7 +1127,7 @@ static header_field_info hfi_netlink_route_rt_flags NETLINK_ROUTE_HFI_INIT =
 	  NULL, 0x00, NULL, HFILL };
 
 static int
-dissect_netlink_route_rtmsg(tvbuff_t *tvb, struct netlink_route_info *info, struct packet_netlink_data *nl_data _U_, proto_tree *tree, int offset)
+dissect_netlink_route_rtmsg(tvbuff_t *tvb, struct netlink_route_info *info, struct packet_netlink_data *nl_data, proto_tree *tree, int offset)
 {
 	proto_tree_add_item(tree, &hfi_netlink_route_rt_family,   tvb, offset, 1, ENC_NA);
 	offset += 1;
@@ -1159,7 +1156,7 @@ dissect_netlink_route_rtmsg(tvbuff_t *tvb, struct netlink_route_info *info, stru
 	proto_tree_add_item(tree, &hfi_netlink_route_rt_type,     tvb, offset, 1, ENC_NA);
 	offset += 1;
 
-	proto_tree_add_item(tree, &hfi_netlink_route_rt_flags,    tvb, offset, 4, info->encoding);
+	proto_tree_add_item(tree, &hfi_netlink_route_rt_flags,    tvb, offset, 4, nl_data->encoding);
 	offset += 4;
 
 	return offset;
@@ -1215,16 +1212,15 @@ static header_field_info hfi_netlink_route_rta_oif NETLINK_ROUTE_HFI_INIT =
 	  NULL, 0x00, NULL, HFILL };
 
 static int
-dissect_netlink_route_route_attrs(tvbuff_t *tvb, void *data, struct packet_netlink_data *nl_data _U_, proto_tree *tree, int rta_type, int offset, int len)
+dissect_netlink_route_route_attrs(tvbuff_t *tvb, void *data _U_, struct packet_netlink_data *nl_data, proto_tree *tree, int rta_type, int offset, int len)
 {
-	struct netlink_route_info *info = (struct netlink_route_info *)data;
 	enum ws_rta_attr_type type = (enum ws_rta_attr_type) rta_type;
 
 	switch (type) {
 		case WS_RTA_IIF:
 			if (len == 4) {
 				proto_item_append_text(tree, ": %u", tvb_get_letohl(tvb, offset));
-				proto_tree_add_item(tree, &hfi_netlink_route_rta_iif, tvb, offset, 4, info->encoding);
+				proto_tree_add_item(tree, &hfi_netlink_route_rta_iif, tvb, offset, 4, nl_data->encoding);
 				return 1;
 			}
 			return 0;
@@ -1232,7 +1228,7 @@ dissect_netlink_route_route_attrs(tvbuff_t *tvb, void *data, struct packet_netli
 		case WS_RTA_OIF:
 			if (len == 4) {
 				proto_item_append_text(tree, ": %u", tvb_get_letohl(tvb, offset));
-				proto_tree_add_item(tree, &hfi_netlink_route_rta_oif, tvb, offset, 4, info->encoding);
+				proto_tree_add_item(tree, &hfi_netlink_route_rta_oif, tvb, offset, 4, nl_data->encoding);
 				return 1;
 			}
 			return 0;
@@ -1287,7 +1283,7 @@ static header_field_info hfi_netlink_route_nd_type NETLINK_ROUTE_HFI_INIT =
 	  NULL, 0x00, NULL, HFILL };
 
 static int
-dissect_netlink_route_ndmsg(tvbuff_t *tvb, struct netlink_route_info *info, struct packet_netlink_data *nl_data _U_, proto_tree *tree, int offset)
+dissect_netlink_route_ndmsg(tvbuff_t *tvb, struct netlink_route_info *info, struct packet_netlink_data *nl_data, proto_tree *tree, int offset)
 {
 	proto_tree_add_item(tree, &hfi_netlink_route_nd_family, tvb, offset, 1, ENC_NA);
 	offset += 1;
@@ -1298,10 +1294,10 @@ dissect_netlink_route_ndmsg(tvbuff_t *tvb, struct netlink_route_info *info, stru
 	/* XXX, 3B padding */
 	offset += 3;
 
-	proto_tree_add_item(tree, &hfi_netlink_route_nd_index, tvb, offset, 4, info->encoding);
+	proto_tree_add_item(tree, &hfi_netlink_route_nd_index, tvb, offset, 4, nl_data->encoding);
 	offset += 4;
 
-	proto_tree_add_item(tree, &hfi_netlink_route_nd_state, tvb, offset, 2, info->encoding);
+	proto_tree_add_item(tree, &hfi_netlink_route_nd_state, tvb, offset, 2, nl_data->encoding);
 	offset += 2;
 
 	proto_tree_add_item(tree, &hfi_netlink_route_nd_flags, tvb, offset, 1, ENC_NA);
@@ -1400,9 +1396,7 @@ dissect_netlink_route(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void
 	/* Netlink message header (nlmsghdr) */
 	offset = dissect_netlink_header(tvb, nlmsg_tree, offset, nl_data->encoding, &hfi_netlink_route_nltype, NULL);
 
-	info.encoding = nl_data->encoding;
 	info.pinfo = pinfo;
-	info.nl_data = nl_data;
 
 	switch (nl_data->type) {
 		case WS_RTM_NEWLINK: