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wireshark/epan/dissectors/packet-ipars.c

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/* packet-ipars.c
* Routines for IPARS/ALC (International Passenger Airline Reservation System/Airline Link Control) WAN protocol dissection
* Copyright 2007, Fulko Hew, SITA INC Canada, Inc.
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
/* NOTE: This should be rewritten to be more in line with how packet-uts.c is
* written so that there are filterable fields available for IPARS too.
*/
#include "config.h"
#include <epan/packet.h>
#include <wsutil/str_util.h>
void proto_register_ipars(void);
static int proto_ipars = -1;
static guint8 ipars_eomtype = G_MAXUINT8;
static gint ett_ipars = -1;
#define S1 (0x00)
#define S2 (0x20)
#define GA (0x03)
#define EOMpb (0x10)
#define EOMc (0x11)
#define EOMu (0x12)
#define EOMi (0x13)
#define MAX_EOM_MSG_SIZE (16) /* max size of an EOMx indicator string */
static int
dissect_ipars(tvbuff_t *tvb, packet_info *pinfo _U_ , proto_tree *tree, void* data _U_)
{
int bytes;
guint8 ia = 0, ta = 0, cmd = 0, la = 0;
tvbuff_t *next_tvb;
int offset = 0;
gchar *eom_msg;
eom_msg = (gchar *)wmem_alloc(pinfo->pool, MAX_EOM_MSG_SIZE);
eom_msg[0] = 0;
col_clear(pinfo->cinfo, COL_INFO);
col_set_str(pinfo->cinfo, COL_PROTOCOL, "IPARS");
if (tvb_captured_length_remaining(tvb, 0) >= 2 ) {
ia = tvb_get_guint8(tvb, 0) & 0x3f;
ta = tvb_get_guint8(tvb, 1) & 0x3f;
if (ia == S1 && ta == S2) { /* if the first two bytes are S1/S2 skip over them */
offset = 2;
}
}
if (tvb_captured_length_remaining(tvb, offset) >= 1) ia = tvb_get_guint8(tvb, offset + 0);
if (tvb_captured_length_remaining(tvb, offset) >= 2) ta = tvb_get_guint8(tvb, offset + 1);
if (ia == 0x83 || ia == 0x43 || ia == GA) { /* if it's an FPGA or 'corresponsdance code' 'go ahead'... */
if (tvb_captured_length_remaining(tvb, offset) > 2) { /* if the msg is long, it must have been a 'poll' */
col_add_fstr(pinfo->cinfo, COL_INFO, "Poll IA: %2.2X", ta);
} else { /* if it's short, then it was a 'no traffic' response */
if (tvb_captured_length_remaining(tvb, offset) >= 2 ) {
col_add_fstr(pinfo->cinfo, COL_INFO, "GoAhead NextIA (0x%2.2X)", ta);
} else {
col_set_str(pinfo->cinfo, COL_INFO, "GoAhead NextIA");
}
}
} else { /* if it's not a 'go ahead'... it must be some kind of data message */
ia &= 0x3f;
ta &= 0x3f;
if (ta == 0x20) {
col_add_fstr(pinfo->cinfo, COL_INFO, "Reset IA: %2.2X", ia); /* the TA character was the 'reset' command */
}
if (tvb_captured_length_remaining(tvb, offset) >= 3) cmd = tvb_get_guint8(tvb, offset + 2) & 0x3f; /* get the first two bytes of the data message */
if (tvb_captured_length_remaining(tvb, offset) >= 4) la = tvb_get_guint8(tvb, offset + 3) & 0x3f;
if (cmd == 0x1f && la == 0x38) {
col_add_fstr(pinfo->cinfo, COL_INFO, "Please Resend - IA: %2.2X TA: %2.2X", ia, ta); /* light the resend indicator */
} else if (cmd == 0x2a && la == 0x05) {
col_add_fstr(pinfo->cinfo, COL_INFO, "Unsolicited Msg Indicator - IA: %2.2X TA: %2.2X", ia, ta); /* light the unsolicited msg indicator */
} else {
col_add_fstr(pinfo->cinfo, COL_INFO, "Data Msg - IA: %2.2X TA: %2.2X", ia, ta); /* it was a data message (display or printer */
}
}
if (tree) {
bytes = tvb_captured_length_remaining(tvb, 0);
if (bytes > 0) {
proto_tree *ipars_tree;
proto_item *ti;
ia = tvb_get_guint8(tvb, 0) & 0x3f;
ti = proto_tree_add_protocol_format(tree, proto_ipars, tvb, 0, -1, "Ipars");
ipars_tree = proto_item_add_subtree(ti, ett_ipars);
if (ia == 0x03) {
proto_tree_add_protocol_format(ipars_tree, proto_ipars, tvb, 0, 1, "GoAhead Next IA");
col_set_str(pinfo->cinfo, COL_INFO, "GoAhead");
return tvb_captured_length(tvb);
} else if (ia != S1) {
proto_tree_add_protocol_format(ipars_tree, proto_ipars, tvb,
0,
bytes, "Unknown format - Data (%d byte%s)", bytes,
plurality(bytes, "", "s"));
return tvb_captured_length(tvb);
}
proto_tree_add_protocol_format(ipars_tree, proto_ipars, tvb, 0, 1, "S1");
ia = tvb_get_guint8(tvb, 1) & 0x3f;
if (ia != S2) {
proto_tree_add_protocol_format(ipars_tree, proto_ipars, tvb,
0,
bytes, "Unknown format - Data (%d byte%s)", bytes,
plurality(bytes, "", "s"));
return tvb_captured_length(tvb);
}
proto_tree_add_protocol_format(ipars_tree, proto_ipars, tvb, 1, 1, "S2");
ia = tvb_get_guint8(tvb, 2) & 0x3f;
if (ia == GA) {
ia = tvb_get_guint8(tvb, 3) & 0x3f;
proto_tree_add_protocol_format(ipars_tree, proto_ipars, tvb, 2, 2, "GoAhead IA: %2.2X", ia);
ipars_eomtype = tvb_get_guint8(tvb, 4) & 0x3f;
switch (ipars_eomtype) {
case EOMc: snprintf(eom_msg, MAX_EOM_MSG_SIZE, "EOMc"); break;
case EOMi: snprintf(eom_msg, MAX_EOM_MSG_SIZE, "EOMi"); break;
case EOMu: snprintf(eom_msg, MAX_EOM_MSG_SIZE, "EOMu"); break;
case EOMpb: snprintf(eom_msg, MAX_EOM_MSG_SIZE, "EOMpb"); break;
default: snprintf(eom_msg, MAX_EOM_MSG_SIZE, "Unknown EOM type (0x%2.2X)", ia); break;
}
proto_tree_add_protocol_format(ipars_tree, proto_ipars, tvb, 4, 1, "%s", eom_msg);
proto_tree_add_protocol_format(ipars_tree, proto_ipars, tvb, 5, 1, "Good BCC");
} else {
next_tvb = tvb_new_subset_remaining(tvb, 3);
proto_tree_add_protocol_format(ipars_tree, proto_ipars, next_tvb,
0,
bytes, "Data (%d byte%s)", bytes,
plurality(bytes, "", "s"));
return tvb_captured_length(tvb);
}
}
}
return tvb_captured_length(tvb);
}
void
proto_register_ipars(void)
{
static gint *ett[] = {
&ett_ipars,
};
proto_ipars = proto_register_protocol("International Passenger Airline Reservation System", "IPARS", "ipars");
proto_register_subtree_array(ett, array_length(ett));
register_dissector("ipars", dissect_ipars, proto_ipars);
}
/*
* Editor modelines - https://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 4
* tab-width: 8
* indent-tabs-mode: nil
* End:
*
* vi: set shiftwidth=4 tabstop=8 expandtab:
* :indentSize=4:tabSize=8:noTabs=true:
*/
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