Wireshark · Ethereal-dev: [ethereal-dev] Minor bug fix and enhancement [Patch included]

[Philip Gladstone <philip@xxxxxxxxxx>]

Hi,
    Attached is a minor fix so that the tree view displays nicely with
more recent
versions of gtk. (to be applied to gtk/main.c)

    Attached is a minor enhancement to packet-ip.c that tells you
whether the IP
checksum is correct or incorrect. I added this while trying to track
down a bizarre
problem that turned out to be that some packets had incorrect checksums!

--
Philip Gladstone                           +1 781 530 2461
Axent Technologies, Waltham, MA

Index: gtk/main.c
===================================================================
RCS file: /cvsroot/ethereal/gtk/main.c,v
retrieving revision 1.65
diff -u -b -r1.65 main.c
--- main.c	1999/12/07 22:59:18	1.65
+++ main.c	1999/12/08 16:46:30
@@ -1262,7 +1262,7 @@
   gtk_tree_set_selection_mode(GTK_TREE(tree_view), GTK_SELECTION_SINGLE);
 
   /* XXX - what's the difference between the next two lines? */
-  gtk_tree_set_view_lines(GTK_TREE(tree_view), FALSE);
+  gtk_tree_set_view_lines(GTK_TREE(tree_view), TRUE);
   gtk_tree_set_view_mode(GTK_TREE(tree_view), GTK_TREE_VIEW_ITEM);
 
   gtk_signal_connect(GTK_OBJECT(tree_view), "selection_changed",

Index: packet-ip.c
===================================================================
RCS file: /cvsroot/ethereal/packet-ip.c,v
retrieving revision 1.64
diff -u -b -r1.64 packet-ip.c
--- packet-ip.c	1999/11/21 14:43:52	1.64
+++ packet-ip.c	1999/12/08 16:46:16
@@ -749,6 +749,26 @@
   "Not set"
 };
 
+static char *ip_checksum_state(e_ip *iph)
+{
+    unsigned long Sum;
+    unsigned short *Ptr, *PtrEnd;
+    
+    Sum    = 0;
+    PtrEnd = (unsigned short *) (lo_nibble(iph->ip_v_hl) * 4 + (char *)iph);
+    for (Ptr = (unsigned short *) iph; Ptr < PtrEnd; Ptr++) {
+        Sum += *Ptr;
+    }
+
+    Sum = (Sum & 0xFFFF) + (Sum >> 16);
+    Sum = (Sum & 0xFFFF) + (Sum >> 16);
+
+    if (Sum != 0xffff)
+        return "incorrect";
+
+    return "correct";
+}
+
 void
 dissect_ip(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) {
   e_ip       iph;
@@ -864,7 +884,8 @@
     proto_tree_add_item(ip_tree, hf_ip_ttl, offset +  8, 1, iph.ip_ttl);
     proto_tree_add_item_format(ip_tree, hf_ip_proto, offset +  9, 1, iph.ip_p,
 	"Protocol: %s (0x%02x)", ipprotostr(iph.ip_p), iph.ip_p);
-    proto_tree_add_item(ip_tree, hf_ip_checksum, offset + 10, 2, iph.ip_sum);
+    proto_tree_add_item_format(ip_tree, hf_ip_checksum, offset + 10, 2, iph.ip_sum,
+        "Header checksum: 0x%04x (%s)", iph.ip_sum, ip_checksum_state((e_ip*) &pd[offset]));
     proto_tree_add_item(ip_tree, hf_ip_src, offset + 12, 4, iph.ip_src);
     proto_tree_add_item(ip_tree, hf_ip_dst, offset + 16, 4, iph.ip_dst);
     proto_tree_add_item_hidden(ip_tree, hf_ip_addr, offset + 12, 4, iph.ip_src);