Add proto_tree_add_checksum.

This is an attempt to standardize display/handling of checksum fields for all dissectors.
The main target is for dissectors that do validation, but dissectors that just report the
checksum were also included just to make them easier to find in the future.

Bug: 10620
Bug: 12058
Ping-Bug: 8859
Change-Id: Ia8abd86e42eaf8ed50de6b173409e914b17993bf
Reviewed-on: https://code.wireshark.org/review/16380
Petri-Dish: Michael Mann <mmann78@netscape.net>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Jeff Morriss <jeff.morriss.ws@gmail.com>
Reviewed-by: Michael Mann <mmann78@netscape.net>

1 files changed, 12 insertions, 21 deletions

diff --git a/epan/dissectors/packet-teamspeak2.c b/epan/dissectors/packet-teamspeak2.c
index 3febde13f3..388dd4dba1 100644
--- a/epan/dissectors/packet-teamspeak2.c
+++ b/epan/dissectors/packet-teamspeak2.c
@@ -304,7 +304,7 @@ typedef struct
 static reassembly_table msg_reassembly_table;
 
 /* forward reference */
-static gboolean ts2_add_checked_crc32(proto_tree *tree, int hf_item, tvbuff_t *tvb, guint16 offset, guint32 icrc32);
+static void ts2_add_checked_crc32(proto_tree *tree, int hf_item, tvbuff_t *tvb, guint16 offset);
 static void ts2_parse_playerlist(tvbuff_t *tvb, proto_tree *ts2_tree);
 static void ts2_parse_channellist(tvbuff_t *tvb, proto_tree *ts2_tree);
 static void ts2_parse_newplayerjoined(tvbuff_t *tvb, proto_tree *ts2_tree);
@@ -421,7 +421,7 @@ static void ts2_standard_dissect(tvbuff_t *tvb, packet_info *pinfo, proto_tree *
 
     proto_tree_add_item(ts2_tree, hf_ts2_resend_count, tvb, 16, 2, ENC_LITTLE_ENDIAN);
     proto_tree_add_item(ts2_tree, hf_ts2_fragmentnumber, tvb, 18, 2, ENC_LITTLE_ENDIAN);
-    ts2_add_checked_crc32(ts2_tree, hf_ts2_crc32, tvb, 20, tvb_get_letohl(tvb, 20));
+    ts2_add_checked_crc32(ts2_tree, hf_ts2_crc32, tvb, 20);
 
     /* Reassemble the packet if it's fragmented */
     new_tvb = NULL;
@@ -764,7 +764,7 @@ static int dissect_ts2(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void
         {
             case TS2C_CONNECTION:
                 proto_tree_add_item(ts2_tree, hf_ts2_seqnum, tvb, 12, 4, ENC_LITTLE_ENDIAN);
-                ts2_add_checked_crc32(ts2_tree, hf_ts2_crc32, tvb, 16, tvb_get_letohl(tvb, 16));
+                ts2_add_checked_crc32(ts2_tree, hf_ts2_crc32, tvb, 16);
 
                 switch(type)
                 {
@@ -816,29 +816,20 @@ static int dissect_ts2(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void
 /* Calculates a CRC32 checksum from the tvb zeroing out four bytes at the offset and checks it with the given crc32 and adds the result to the tree
  * Returns true if the calculated CRC32 matches the passed CRC32.
  * */
-static gboolean ts2_add_checked_crc32(proto_tree *tree, int hf_item, tvbuff_t *tvb, guint16 offset, guint32 icrc32 )
+static void ts2_add_checked_crc32(proto_tree *tree, int hf_item, tvbuff_t *tvb, guint16 offset)
 {
-    guint8  *zero;
-    gint     len;
+    guint32  zero = 0;
+    gint     len = tvb_reported_length_remaining(tvb, offset+4);
     guint32  ocrc32;
 
-    zero = (guint8 *)wmem_alloc0(wmem_packet_scope(), 4);
-    ocrc32 = crc32_ccitt_tvb(tvb, offset);
-    ocrc32 = crc32_ccitt_seed(zero, 4, 0xffffffff-ocrc32);
-    len = tvb_reported_length_remaining(tvb, offset+4);
     if (len<0)
-        return FALSE;
+        return;
+
+    ocrc32 = crc32_ccitt_tvb(tvb, offset);
+    ocrc32 = crc32_ccitt_seed((guint8*)&zero, 4, 0xffffffff-ocrc32);
     ocrc32 = crc32_ccitt_tvb_offset_seed(tvb, offset+4, (guint)len, 0xffffffff-ocrc32);
-    if(icrc32==ocrc32)
-    {
-        proto_tree_add_uint_format(tree, hf_item, tvb, offset, 4, tvb_get_letohl(tvb, 16), "crc32: 0x%04x [correct]", tvb_get_letohl(tvb, offset));
-        return TRUE;
-    }
-    else
-    {
-        proto_tree_add_uint_format(tree, hf_item, tvb, offset, 4, tvb_get_letohl(tvb,16), "crc32: 0x%04x [incorrect, should be 0x%04x]", tvb_get_letohl(tvb, offset),ocrc32);
-        return FALSE;
-    }
+
+    proto_tree_add_checksum(tree, tvb, offset, hf_item, -1, NULL, NULL, ocrc32, ENC_LITTLE_ENDIAN, PROTO_CHECKSUM_VERIFY);
 }
 
 static void ts2_init(void)