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From Gerasimos Dimitriadis: 

DTAP: Decoding of Text String in Network Name IE

https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=4121

svn path=/trunk/; revision=30571
This commit is contained in:
Anders Broman 2009-10-16 10:38:42 +00:00
parent c6620d7770
commit 77c3bfd8c1
1 changed files with 63 additions and 12 deletions
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75
epan/dissectors/packet-gsm_a_dtap.c
View File

@ -99,6 +99,8 @@
#include "packet-ipv6.h"
#include "packet-e212.h"
#include "packet-ppp.h"
#include "packet-gsm_sms.h"
#include "expert.h"
/* PROTOTYPES/FORWARDS */
@ -612,6 +614,12 @@ de_network_name(tvbuff_t *tvb, proto_tree *tree, guint32 offset, guint len, gcha
guint8 oct;
guint32 curr_offset;
const gchar *str;
guint8 coding_scheme, num_spare_bits;
guint32 num_chars, num_text_bits;
gchar *net_name = NULL;
GIConv cd;
GError *l_conv_error = NULL;
proto_item *item;
curr_offset = offset;
@ -619,9 +627,10 @@ de_network_name(tvbuff_t *tvb, proto_tree *tree, guint32 offset, guint len, gcha
proto_tree_add_item(tree, hf_gsm_a_extension, tvb, curr_offset, 1, FALSE);
switch ((oct & 0x70) >> 4)
coding_scheme = (oct & 0x70) >> 4;
switch (coding_scheme)
{
case 0x00: str = "Cell Broadcast data coding scheme, GSM default alphabet, language unspecified, defined in 3GPP TS 03.38"; break;
case 0x00: str = "Cell Broadcast data coding scheme, GSM default alphabet, language unspecified, defined in 3GPP TS 23.038"; break;
case 0x01: str = "UCS2 (16 bit)"; break;
default:
str = "Reserved";
@ -642,9 +651,10 @@ de_network_name(tvbuff_t *tvb, proto_tree *tree, guint32 offset, guint len, gcha
a_bigbuf,
(oct & 0x08) ?
"add the letters for the Country's Initials and a separator (e.g. a space) to the text string" :
"The MS should not add the letters for the Country's Initials to the text string");
"not add the letters for the Country's Initials to the text string");
switch (oct & 0x07)
num_spare_bits = oct & 0x07;
switch (num_spare_bits)
{
case 1: str = "bit 8 is spare and set to '0' in octet n"; break;
case 2: str = "bits 7 and 8 are spare and set to '0' in octet n"; break;
@ -659,7 +669,7 @@ de_network_name(tvbuff_t *tvb, proto_tree *tree, guint32 offset, guint len, gcha
}
other_decode_bitfield_value(a_bigbuf, oct, 0x07, 8);
proto_tree_add_text(tree,
item = proto_tree_add_text(tree,
tvb, curr_offset, 1,
"%s : Number of spare bits in last octet: %s",
a_bigbuf,
@ -668,16 +678,57 @@ de_network_name(tvbuff_t *tvb, proto_tree *tree, guint32 offset, guint len, gcha
curr_offset++;
NO_MORE_DATA_CHECK(len);
switch(coding_scheme)
{
case 0:
num_chars = gsm_sms_char_7bit_unpack(0, len - 1, sizeof(a_bigbuf),
tvb_get_ptr(tvb, curr_offset, len - 1), a_bigbuf);
proto_tree_add_text(tree,
tvb, curr_offset, len - 1,
"Text string encoded according to Coding Scheme");
/* Check if there was a reasonable value for number of spare bits in last octet */
num_text_bits = ((len - 1) << 3) - num_spare_bits;
if (num_spare_bits && (num_text_bits % 7))
{
expert_add_info_format(gsm_a_dtap_pinfo, item, PI_MALFORMED, PI_WARN, "Value leads to a Text String whose length is not a multiple of 7 bits");
}
/*
* If the number of spare bits is 7, then we have unpacked one extra
* character. Disregard this character.
*/
if (num_spare_bits == 7)
num_chars--;
a_bigbuf[num_chars] = '\0';
/* There could be Greek chars, so better be safe */
net_name = ep_alloc(2 * num_chars);
gsm_sms_char_ascii_decode(net_name, a_bigbuf, num_chars);
proto_tree_add_text(tree, tvb , curr_offset, len - 1, "Text String: %s", net_name);
break;
case 1:
if ((cd = g_iconv_open("UTF-8","UCS-2BE")) != (GIConv)-1)
{
net_name = g_convert_with_iconv(tvb_get_ptr(tvb, curr_offset, len - 1), len - 1, cd, NULL, NULL, &l_conv_error);
if(!l_conv_error){
proto_tree_add_text(tree, tvb, curr_offset, len - 1, "Text String: %s", net_name);
}else{
proto_tree_add_text(tree, tvb, curr_offset, len - 1, "Failed on UCS2 contact wireshark developers");
}
curr_offset += len - 1;
g_free(net_name);
g_iconv_close(cd);
}
else
{
/* tvb_get_ephemeral_faked_unicode takes the length in number of guint16's */
net_name = tvb_get_ephemeral_faked_unicode(tvb, curr_offset, ((len - 1) >> 1), FALSE);
proto_tree_add_text(tree, tvb, curr_offset, len - 1, "Text String: %s", net_name);
}
break;
default:
proto_tree_add_text(tree,
tvb, curr_offset, len - 1,
"Text string encoded according to an unknown Coding Scheme");
}
EXTRANEOUS_DATA_CHECK(len, curr_offset - offset);
return(curr_offset - offset);
return(len);
}
/* 3GPP TS 24.008