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When reassembling, test the correct M bit based on whether it's mod-8 or 

mod-128.

Don't reassemble if we don't have all the payload (e.g., if we have a
short frame).

Clean up indentation.

Remove the "_x25" at the end of the preference for reassembling X.25
packets - it already has "x25." at the beginning.

Add a bunch of #defines for various bits to be tested, and use them.

svn path=/trunk/; revision=7279
This commit is contained in:
Guy Harris 2003-03-05 01:12:11 +00:00
parent 043ef892af
commit bc0799079d
1 changed files with 47 additions and 32 deletions
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79
packet-x25.c
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@ -2,7 +2,7 @@
* Routines for X.25 packet disassembly
* Olivier Abad <oabad@noos.fr>
*
* $Id: packet-x25.c,v 1.81 2003/03/04 19:50:20 guy Exp $
* $Id: packet-x25.c,v 1.82 2003/03/05 01:12:11 guy Exp $
*
* Ethereal - Network traffic analyzer
* By Gerald Combs <gerald@ethereal.com>
@ -74,6 +74,14 @@ typedef enum {
#define PACKET_IS_DATA(type) (!(type & X25_NONDATA_BIT))
#define PACKET_TYPE_FC(type) (type & 0x1F)
#define X25_MBIT_MOD8 0x10
#define X25_MBIT_MOD128 0x01
#define X25_ABIT 0x8000
#define X25_QBIT 0x8000
#define X25_DBIT 0x4000
#define X25_FAC_CLASS_MASK 0xC0
#define X25_FAC_CLASS_A 0x00
@ -1452,6 +1460,8 @@ dissect_x25_common(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
char *short_name = NULL, *long_name = NULL;
tvbuff_t *next_tvb = NULL;
gboolean q_bit_set = FALSE;
gboolean m_bit_set;
gint payload_len;
void *saved_private_data;
fragment_data *fd_head;
@ -1466,7 +1476,7 @@ dissect_x25_common(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
pinfo->ctype = CT_X25;
pinfo->circuit_id = vc;
if (bytes0_1 & 0x8000) toa = TRUE;
if (bytes0_1 & X25_ABIT) toa = TRUE;
else toa = FALSE;
x25_pkt_len = get_x25_pkt_len(tvb);
@ -1482,7 +1492,7 @@ dissect_x25_common(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
pkt_type = tvb_get_guint8(tvb, 2);
if (PACKET_IS_DATA(pkt_type)) {
if (bytes0_1 & 0x8000)
if (bytes0_1 & X25_QBIT)
q_bit_set = TRUE;
}
@ -2074,13 +2084,13 @@ dissect_x25_common(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
"Data VC:%d P(S):%d P(R):%d %s", vc,
(pkt_type >> 1) & 0x07,
(pkt_type >> 5) & 0x07,
((pkt_type >> 4) & 0x01) ? " M" : "");
(pkt_type & X25_MBIT_MOD8) ? " M" : "");
else
col_add_fstr(pinfo->cinfo, COL_INFO,
"Data VC:%d P(S):%d P(R):%d %s", vc,
tvb_get_guint8(tvb, localoffset+1) >> 1,
pkt_type >> 1,
(tvb_get_guint8(tvb, localoffset+1) & 0x01) ? " M" : "");
(tvb_get_guint8(tvb, localoffset+1) & X25_MBIT_MOD128) ? " M" : "");
}
if (x25_tree) {
proto_tree_add_uint(x25_tree, hf_x25_lcn, tvb, localoffset-2,
@ -2108,31 +2118,36 @@ dissect_x25_common(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
tvb_get_guint8(tvb, localoffset+1));
}
}
localoffset += (modulo == 8) ? 1 : 2;
if (reassemble_x25)
{
if (modulo == 8) {
m_bit_set = pkt_type & X25_MBIT_MOD8;
localoffset += 1;
} else {
m_bit_set = tvb_get_guint8(tvb, localoffset+1) & X25_MBIT_MOD128;
localoffset += 2;
}
payload_len = tvb_reported_length_remaining(tvb, localoffset);
if (reassemble_x25 && tvb_bytes_exist(tvb, localoffset, payload_len)) {
fd_head = fragment_add_seq_next(tvb, localoffset,
pinfo, vc, x25_segment_table,
x25_reassembled_table,
tvb_reported_length(tvb) - localoffset,
(pkt_type >> 4) & 0x01);
pinfo->fragmented = (pkt_type >> 4) & 0x01;
payload_len, m_bit_set);
pinfo->fragmented = m_bit_set;
if (fd_head)
if (fd_head->next)
{
/* This is the last packet */
next_tvb = tvb_new_real_data(fd_head->data,
fd_head->len,
fd_head->len);
tvb_set_child_real_data_tvbuff(tvb, next_tvb);
add_new_data_source(pinfo, next_tvb, "Reassembled X25");
show_fragment_seq_tree(fd_head,
&x25_frag_items,
x25_tree,
pinfo, next_tvb);
}
}
if (fd_head) {
if (fd_head->next) {
/* This is the last packet */
next_tvb = tvb_new_real_data(fd_head->data,
fd_head->len,
fd_head->len);
tvb_set_child_real_data_tvbuff(tvb, next_tvb);
add_new_data_source(pinfo, next_tvb, "Reassembled X.25");
show_fragment_seq_tree(fd_head,
&x25_frag_items,
x25_tree,
pinfo, next_tvb);
}
}
}
break;
}
switch (PACKET_TYPE_FC(pkt_type))
@ -2319,13 +2334,13 @@ proto_register_x25(void)
{ "GFI", "x.25.gfi", FT_UINT16, BASE_DEC, NULL, 0xF000,
"General format identifier", HFILL }},
{ &hf_x25_abit,
{ "A Bit", "x.25.a", FT_BOOLEAN, 16, NULL, 0x8000,
{ "A Bit", "x.25.a", FT_BOOLEAN, 16, NULL, X25_ABIT,
"Address Bit", HFILL }},
{ &hf_x25_qbit,
{ "Q Bit", "x.25.q", FT_BOOLEAN, 16, NULL, 0x8000,
{ "Q Bit", "x.25.q", FT_BOOLEAN, 16, NULL, X25_QBIT,
"Qualifier Bit", HFILL }},
{ &hf_x25_dbit,
{ "D Bit", "x.25.d", FT_BOOLEAN, 16, NULL, 0x4000,
{ "D Bit", "x.25.d", FT_BOOLEAN, 16, NULL, X25_DBIT,
"Delivery Confirmation Bit", HFILL }},
{ &hf_x25_mod,
{ "Modulo", "x.25.mod", FT_UINT16, BASE_DEC, VALS(vals_modulo), 0x3000,
@ -2349,10 +2364,10 @@ proto_register_x25(void)
{ "P(R)", "x.25.p_r", FT_UINT8, BASE_DEC, NULL, 0xFE,
"Packet Receive Sequence Number", HFILL }},
{ &hf_x25_mbit_mod8,
{ "M Bit", "x.25.m", FT_BOOLEAN, 8, TFS(&m_bit_tfs), 0x10,
{ "M Bit", "x.25.m", FT_BOOLEAN, 8, TFS(&m_bit_tfs), X25_MBIT_MOD8,
"More Bit", HFILL }},
{ &hf_x25_mbit_mod128,
{ "M Bit", "x.25.m", FT_BOOLEAN, 8, TFS(&m_bit_tfs), 0x01,
{ "M Bit", "x.25.m", FT_BOOLEAN, 8, TFS(&m_bit_tfs), X25_MBIT_MOD128,
"More Bit", HFILL }},
{ &hf_x25_p_s_mod8,
{ "P(S)", "x.25.p_s", FT_UINT8, BASE_DEC, NULL, 0x0E,
@ -2436,7 +2451,7 @@ proto_register_x25(void)
"Default to QLLC/SNA",
"If CALL REQUEST not seen or didn't specify protocol, dissect as QLLC/SNA",
&payload_is_qllc_sna);
prefs_register_bool_preference(x25_module, "reassemble_x25",
prefs_register_bool_preference(x25_module, "reassemble",
"Reassemble fragmented X.25 packets",
"Reassemble fragmented X.25 packets",
&reassemble_x25);