u_char identifier and abs_time_to_str

Question

I am trying to adapt an old code packet-gtpcdr.c into new version of wireshark but failed during compilation.

If I rename the u_char to gchar the complilation continue. I am not sure if this is correct.

/* TAG undefined */
int decode_tlv_undefined (tvbuff_t *tvb, proto_tree *tree, int offset) {
    proto_tree  *tlv_tree;
    proto_item  *te;
    u_char  length, tag;
    tag = tvb_get_guint8 (tvb, offset);
    length = tvb_get_guint8 (tvb, offset + 1);
    te = proto_tree_add_text (tree, tvb, offset, length + 2, "TAG %d (undefined)", tag);
    tlv_tree = proto_item_add_subtree (te, ett_gtp_cdr_undefined);
    proto_tree_add_text (tlv_tree, tvb, offset, 1, "Type: %d", tag);
    proto_tree_add_text (tlv_tree, tvb, offset + 1, 1, "Length: %d", length);
    proto_tree_add_text (tlv_tree, tvb, offset + 2, length, "Value");

Which additional value should I add for abs_time_to_str?

static gchar *
time_int_to_str (guint32 time)
{
    static nstime_t nstime;
    nstime.secs = time;
    nstime.nsecs = 0;
    return abs_time_to_str (&nstime);

See the compile error

packet-gtpcdr.c
plugin.c
packet-gtpcdr.c(2573) : error C2198: 'abs_time_to_str' : too few arguments for call
packet-gtpcdr.c(3901) : error C2065: 'uchar' : undeclared identifier
packet-gtpcdr.c(3901) : error C2146: syntax error : missing ';' before identifier 'length'
packet-gtpcdr.c(3901) : error C2065: 'length' : undeclared identifier
packet-gtpcdr.c(3901) : error C2065: 'tag' : undeclared identifier
packet-gtpcdr.c(3903) : error C2065: 'tag' : undeclared identifier
packet-gtpcdr.c(3904) : error C2065: 'length' : undeclared identifier
packet-gtpcdr.c(3906) : error C2065: 'length' : undeclared identifier
packet-gtpcdr.c(3906) : error C2065: 'tag' : undeclared identifier
packet-gtpcdr.c(3909) : error C2065: 'tag' : undeclared identifier
packet-gtpcdr.c(3910) : error C2065: 'length' : undeclared identifier
packet-gtpcdr.c(3911) : error C2065: 'length' : undeclared identifier
packet-gtpcdr.c(3913) : error C2065: 'length' : undeclared identifier
packet-gtpcdr.c(3921) : error C2065: 'uchar' : undeclared identifier
packet-gtpcdr.c(3921) : error C2146: syntax error : missing ';' before identifier 'length'

Thanks

Answer 1

You should replace your u_char by guint8. Moreover the prototype of abs_time_to_str is now:

gchar* abs_time_to_str(const nstime_t*, const absolute_time_display_e fmt, gboolean show_zone);

so your code should be:

static gchar *
time_int_to_str (guint32 time)
{
    static nstime_t nstime;
    nstime.secs = time;
    nstime.nsecs = 0;
    return abs_time_to_str (&nstime, ABSOLUTE_TIME_UTC, FALSE);
}

Answer 2

If I rename the u_char to gchar the complilation continue. I am not sure if this is correct.

uchar, u_char, etc. are types defined by the operating system on which you're compiling; they should be avoided, so that the code can compile on several operating systems (including Windows, which is what you're compiling on).

Instead, the GLib types should be used; for example, for an 8-bit unsigned integral quantity, use guint8. (Oh, and since it's unsigned, format it with %u, not %d.)

Which additional value should I add for abs_time_to_str?

You should add, as the second argument:

ABSOLUTE_TIME_LOCAL, if you want the time stamp displayed as local date and time, with the date shown as a month, day, and year;
ABSOLUTE_TIME_UTC, if you want the time stamp displayed as UTC date and time, with the date shown as a month, day, and year;
ABSOLUTE_TIME_DOY_UTC, if you want the time stamp displayed as UTC date and time, with the date shown as day-of-year and year, with January 1 being day-of-year 1.