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, 9 insertions, 48 deletions

diff --git a/epan/dissectors/packet-eth.c b/epan/dissectors/packet-eth.c
index bfb6cc5270..4d82e8f448 100644
--- a/epan/dissectors/packet-eth.c
+++ b/epan/dissectors/packet-eth.c
@@ -78,14 +78,12 @@ static int hf_eth_ig = -1;
 static int hf_eth_padding = -1;
 static int hf_eth_trailer = -1;
 static int hf_eth_fcs = -1;
-static int hf_eth_fcs_good = -1;
-static int hf_eth_fcs_bad = -1;
+static int hf_eth_fcs_status = -1;
 
 static gint ett_ieee8023 = -1;
 static gint ett_ether2 = -1;
 static gint ett_ether = -1;
 static gint ett_addr = -1;
-static gint ett_eth_fcs = -1;
 
 static expert_field ei_eth_invalid_lentype = EI_INIT;
 static expert_field ei_eth_src_not_group = EI_INIT;
@@ -647,8 +645,6 @@ add_ethernet_trailer(packet_info *pinfo, proto_tree *tree, proto_tree *fh_tree,
      have had 64 or more bytes - i.e., it was at least an FCS worth of data
      longer than the minimum payload size - we could assume the last 4 bytes
      of the trailer are an FCS. */
-  proto_item *item;
-  proto_tree *checksum_tree;
   heur_dtbl_entry_t *hdtbl_entry;
 
   if (trailer_tvb) {
@@ -749,43 +745,13 @@ add_ethernet_trailer(packet_info *pinfo, proto_tree *tree, proto_tree *fh_tree,
       guint32 sent_fcs = tvb_get_ntohl(trailer_tvb, padding_length+trailer_length);
       if(eth_check_fcs){
         guint32 fcs = crc32_802_tvb(tvb, tvb_captured_length(tvb) - 4);
-        if (fcs == sent_fcs) {
-          item = proto_tree_add_uint_format_value(fh_tree, hf_eth_fcs, trailer_tvb,
-                                            padding_length+trailer_length, 4, sent_fcs,
-                                            "0x%08x [correct]", sent_fcs);
-          checksum_tree = proto_item_add_subtree(item, ett_eth_fcs);
-          item = proto_tree_add_boolean(checksum_tree, hf_eth_fcs_good, trailer_tvb,
-                                        padding_length+trailer_length, 4, TRUE);
-          PROTO_ITEM_SET_GENERATED(item);
-          item = proto_tree_add_boolean(checksum_tree, hf_eth_fcs_bad, trailer_tvb,
-                                        padding_length+trailer_length, 4, FALSE);
-          PROTO_ITEM_SET_GENERATED(item);
-        } else {
-          item = proto_tree_add_uint_format_value(fh_tree, hf_eth_fcs, trailer_tvb,
-                                            padding_length+trailer_length, 4, sent_fcs,
-                                            "0x%08x [incorrect, should be 0x%08x]",
-                                            sent_fcs, fcs);
-          checksum_tree = proto_item_add_subtree(item, ett_eth_fcs);
-          item = proto_tree_add_boolean(checksum_tree, hf_eth_fcs_good, trailer_tvb,
-                                        padding_length+trailer_length, 4, FALSE);
-          PROTO_ITEM_SET_GENERATED(item);
-          item = proto_tree_add_boolean(checksum_tree, hf_eth_fcs_bad, trailer_tvb,
-                                        padding_length+trailer_length, 4, TRUE);
-          PROTO_ITEM_SET_GENERATED(item);
-          expert_add_info(pinfo, item, &ei_eth_fcs_bad);
+        proto_tree_add_checksum(fh_tree, trailer_tvb, padding_length+trailer_length, hf_eth_fcs, hf_eth_fcs_status, &ei_eth_fcs_bad, pinfo, fcs, ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);
+
+        if (fcs != sent_fcs) {
           col_append_str(pinfo->cinfo, COL_INFO, " [ETHERNET FRAME CHECK SEQUENCE INCORRECT]");
         }
       }else{
-        item = proto_tree_add_uint_format_value(fh_tree, hf_eth_fcs, trailer_tvb,
-                                          padding_length+trailer_length, 4, sent_fcs,
-                                          "0x%08x [validation disabled]", sent_fcs);
-        checksum_tree = proto_item_add_subtree(item, ett_eth_fcs);
-        item = proto_tree_add_boolean(checksum_tree, hf_eth_fcs_good, trailer_tvb,
-                                      padding_length+trailer_length, 4, FALSE);
-        PROTO_ITEM_SET_GENERATED(item);
-        item = proto_tree_add_boolean(checksum_tree, hf_eth_fcs_bad, trailer_tvb,
-                                      padding_length+trailer_length, 4, FALSE);
-        PROTO_ITEM_SET_GENERATED(item);
+        proto_tree_add_checksum(fh_tree, trailer_tvb, padding_length+trailer_length, hf_eth_fcs, hf_eth_fcs_status, &ei_eth_fcs_bad, pinfo, 0, ENC_BIG_ENDIAN, PROTO_CHECKSUM_NO_FLAGS);
       }
       trailer_length += 4;
     }
@@ -919,13 +885,9 @@ proto_register_eth(void)
       { "Frame check sequence", "eth.fcs", FT_UINT32, BASE_HEX, NULL, 0x0,
         "Ethernet checksum", HFILL }},
 
-    { &hf_eth_fcs_good,
-      { "FCS Good", "eth.fcs_good", FT_BOOLEAN, BASE_NONE, NULL, 0x0,
-        "True: checksum matches packet content; False: doesn't match content or not checked", HFILL }},
-
-    { &hf_eth_fcs_bad,
-      { "FCS Bad", "eth.fcs_bad", FT_BOOLEAN, BASE_NONE, NULL, 0x0,
-        "True: checksum doesn't match packet content; False: does match content or not checked", HFILL }},
+    { &hf_eth_fcs_status,
+      { "FCS Status", "eth.fcs.status", FT_UINT8, BASE_NONE, VALS(proto_checksum_vals), 0x0,
+        NULL, HFILL }},
 
     { &hf_eth_lg,
       { "LG bit", "eth.lg", FT_BOOLEAN, 24,
@@ -942,13 +904,12 @@ proto_register_eth(void)
     &ett_ether2,
     &ett_ether,
     &ett_addr,
-    &ett_eth_fcs
   };
 
   static ei_register_info ei[] = {
     { &ei_eth_invalid_lentype, { "eth.invalid_lentype.expert", PI_PROTOCOL, PI_WARN, "Invalid length/type", EXPFILL }},
     { &ei_eth_src_not_group, { "eth.src_not_group", PI_PROTOCOL, PI_WARN, "Source MAC must not be a group address: IEEE 802.3-2002, Section 3.2.3(b)", EXPFILL }},
-    { &ei_eth_fcs_bad, { "eth.fcs_bad.expert", PI_CHECKSUM, PI_ERROR, "Bad checksum", EXPFILL }},
+    { &ei_eth_fcs_bad, { "eth.fcs_bad", PI_CHECKSUM, PI_ERROR, "Bad checksum", EXPFILL }},
     { &ei_eth_len, { "eth.len.past_end", PI_MALFORMED, PI_ERROR, "Length field value goes past the end of the payload", EXPFILL }},
   };