From Tomas Kukosa: reassemble segmented Q.931 messages.
svn path=/trunk/; revision=10124
This commit is contained in:
Guy Harris
parent
257a117d11
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cea8bc3801
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AUTHORS
1
AUTHORS
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@ -1040,6 +1040,7 @@ Tomas Kukosa <tomas.kukosa [AT] siemens.com> {
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Support in Wiretap for DLT_HHDLC
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Fix to summary-printing code to handle reallocated line buffer
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Support for registering subdissectors for Q.931 IEs and codesets
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Reassembly of segmented Q.931 messages
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}
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Andreas Stockmeier <a.stockmeier[AT]avm.de> {
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164
packet-q931.c
164
packet-q931.c
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@ -2,7 +2,7 @@
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* Routines for Q.931 frame disassembly
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* Guy Harris <guy@alum.mit.edu>
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*
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* $Id: packet-q931.c,v 1.69 2004/02/18 20:43:37 guy Exp $
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* $Id: packet-q931.c,v 1.70 2004/02/20 10:34:42 guy Exp $
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*
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* Modified by Andreas Sikkema for possible use with H.323
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*
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@ -37,6 +37,7 @@
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#include "nlpid.h"
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#include "packet-q931.h"
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#include "prefs.h"
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#include "reassemble.h"
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#include "lapd_sapi.h"
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#include "packet-tpkt.h"
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@ -74,9 +75,43 @@ static int hf_q931_called_party_number = -1;
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static int hf_q931_connected_number = -1;
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static int hf_q931_redirecting_number = -1;
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static int hf_q931_segments = -1;
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static int hf_q931_segment = -1;
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static int hf_q931_segment_overlap = -1;
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static int hf_q931_segment_overlap_conflict = -1;
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static int hf_q931_segment_multiple_tails = -1;
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static int hf_q931_segment_too_long_segment = -1;
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static int hf_q931_segment_error = -1;
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static int hf_q931_reassembled_in = -1;
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static gint ett_q931 = -1;
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static gint ett_q931_ie = -1;
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static gint ett_q931_segments = -1;
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static gint ett_q931_segment = -1;
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static const fragment_items q931_frag_items = {
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&ett_q931_segment,
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&ett_q931_segments,
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&hf_q931_segments,
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&hf_q931_segment,
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&hf_q931_segment_overlap,
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&hf_q931_segment_overlap_conflict,
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&hf_q931_segment_multiple_tails,
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&hf_q931_segment_too_long_segment,
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&hf_q931_segment_error,
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&hf_q931_reassembled_in,
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"segments"
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};
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/* Tables for reassembly of fragments. */
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static GHashTable *q931_fragment_table = NULL;
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static GHashTable *q931_reassembled_table = NULL;
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/* Preferences */
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static gboolean q931_reassembly = TRUE;
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static dissector_table_t codeset_dissector_table;
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static dissector_table_t ie_dissector_table;
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@ -2285,10 +2320,18 @@ dissect_q931_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
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{
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int offset = 0;
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proto_tree *q931_tree = NULL;
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proto_item *ti;
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proto_tree *ie_tree = NULL;
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proto_item *ti, *ti_ie;
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guint8 call_ref_len;
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guint8 call_ref[15];
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guint8 message_type;
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guint32 call_ref_val;
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guint8 message_type, segmented_message_type;
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guint8 info_element;
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guint16 info_element_len;
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gboolean more_frags;
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guint32 frag_len;
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fragment_data *fd_head;
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tvbuff_t *next_tvb = NULL;
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if (check_col(pinfo->cinfo, COL_PROTOCOL))
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "Q.931");
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@ -2305,6 +2348,13 @@ dissect_q931_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
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if (q931_tree != NULL)
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proto_tree_add_uint(q931_tree, hf_q931_call_ref_len, tvb, offset, 1, call_ref_len);
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offset += 1;
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switch (call_ref_len) {
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case 0: call_ref_val = 0; break;
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case 1: call_ref_val = tvb_get_guint8(tvb, offset); break;
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case 2: call_ref_val = tvb_get_ntohs(tvb, offset); break;
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case 3: call_ref_val = tvb_get_ntoh24(tvb, offset); break;
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default: call_ref_val = tvb_get_ntohl(tvb, offset);
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}
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if (call_ref_len != 0) {
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tvb_memcpy(tvb, call_ref, offset, call_ref_len);
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if (q931_tree != NULL) {
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@ -2329,7 +2379,58 @@ dissect_q931_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
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/*
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* And now for the information elements....
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*/
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dissect_q931_IEs(tvb, pinfo, tree, q931_tree,is_tpkt, offset);
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if ((message_type != Q931_SEGMENT) || !q931_reassembly ||
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(tvb_reported_length_remaining(tvb, offset) <= 4)) {
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dissect_q931_IEs(tvb, pinfo, tree, q931_tree, is_tpkt, offset);
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return;
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}
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info_element = tvb_get_guint8(tvb, offset);
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info_element_len = tvb_get_guint8(tvb, offset + 1);
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if ((info_element != Q931_IE_SEGMENTED_MESSAGE) || (info_element_len < 2)) {
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dissect_q931_IEs(tvb, pinfo, tree, q931_tree, is_tpkt, offset);
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return;
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}
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/* Segmented message IE */
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ti_ie = proto_tree_add_text(q931_tree, tvb, offset, 1+1+info_element_len, "%s",
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val_to_str(info_element, q931_info_element_vals[0], "Unknown information element (0x%02X)"));
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ie_tree = proto_item_add_subtree(ti_ie, ett_q931_ie);
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proto_tree_add_text(ie_tree, tvb, offset, 1, "Information element: %s",
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val_to_str(info_element, q931_info_element_vals[0], "Unknown (0x%02X)"));
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proto_tree_add_text(ie_tree, tvb, offset + 1, 1, "Length: %u", info_element_len);
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dissect_q931_segmented_message_ie(tvb, offset + 2, info_element_len, ie_tree);
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more_frags = (tvb_get_guint8(tvb, offset + 2) & 0x7F) != 0;
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segmented_message_type = tvb_get_guint8(tvb, offset + 3);
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offset += 1 + 1 + info_element_len;
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/* Reassembly */
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frag_len = tvb_length_remaining(tvb, offset);
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fd_head = fragment_add_seq_next(tvb, offset, pinfo, call_ref_val,
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q931_fragment_table, q931_reassembled_table,
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frag_len, more_frags);
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if (fd_head) {
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if (pinfo->fd->num == fd_head->reassembled_in) { /* last fragment */
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if (fd_head->next != NULL) { /* 2 or more segments */
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next_tvb = tvb_new_real_data(fd_head->data, fd_head->len, fd_head->len);
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tvb_set_child_real_data_tvbuff(tvb, next_tvb);
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add_new_data_source(pinfo, next_tvb, "Reassembled Q.931 IEs");
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/* Show all fragments. */
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if (tree) show_fragment_seq_tree(fd_head, &q931_frag_items, q931_tree, pinfo, next_tvb);
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} else { /* only 1 segment */
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next_tvb = tvb_new_subset(tvb, offset, -1, -1);
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}
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if (check_col(pinfo->cinfo, COL_INFO)) {
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col_add_fstr(pinfo->cinfo, COL_INFO, "%s [reassembled]",
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val_to_str(segmented_message_type, q931_message_type_vals, "Unknown message type (0x%02X)"));
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}
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} else {
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if (tree) proto_tree_add_uint(q931_tree, hf_q931_reassembled_in, tvb, offset, frag_len, fd_head->reassembled_in);
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}
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} else {
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if (check_col(pinfo->cinfo, COL_INFO)) {
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col_append_str(pinfo->cinfo, COL_INFO, " [segment]");
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}
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}
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if (next_tvb)
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dissect_q931_IEs(next_tvb, pinfo, tree, q931_tree, is_tpkt, 0);
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}
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static const value_string q931_codeset_vals[] = {
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@ -2842,6 +2943,13 @@ dissect_q931(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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dissect_q931_pdu(tvb, pinfo, tree, FALSE);
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}
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static void
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q931_init(void) {
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/* Initialize the fragment and reassembly tables */
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fragment_table_init(&q931_fragment_table);
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reassembled_table_init(&q931_reassembled_table);
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}
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void
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proto_register_q931(void)
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{
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@ -2922,16 +3030,60 @@ proto_register_q931(void)
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{ &hf_q931_redirecting_number,
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{ "Redirecting party number digits", "q931.redirecting_number.digits", FT_STRING, BASE_NONE, NULL, 0x0,
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"", HFILL }},
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/* desegmentation fields */
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{ &hf_q931_segment_overlap,
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{ "Segment overlap", "q931.segment.overlap",
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FT_BOOLEAN, BASE_NONE, NULL, 0x0,
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"Fragment overlaps with other fragments"}
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},
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{ &hf_q931_segment_overlap_conflict,
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{ "Conflicting data in fragment overlap", "q931.segment.overlap.conflict",
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FT_BOOLEAN, BASE_NONE, NULL, 0x0,
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"Overlapping fragments contained conflicting data"}
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},
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{ &hf_q931_segment_multiple_tails,
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{ "Multiple tail fragments found", "q931.segment.multipletails",
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FT_BOOLEAN, BASE_NONE, NULL, 0x0,
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"Several tails were found when defragmenting the packet"}
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},
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{ &hf_q931_segment_too_long_segment,
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{ "Segment too long", "q931.segment.toolongfragment",
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FT_BOOLEAN, BASE_NONE, NULL, 0x0,
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"Segment contained data past end of packet"}
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},
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{ &hf_q931_segment_error,
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{ "Defragmentation error", "q931.segment.error",
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FT_FRAMENUM, BASE_NONE, NULL, 0x0,
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"Defragmentation error due to illegal fragments"}
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},
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{ &hf_q931_segment,
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{ "Q.931 Segment", "q931.segment",
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FT_FRAMENUM, BASE_NONE, NULL, 0x0,
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"Q.931 Segment"}
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},
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{ &hf_q931_segments,
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{ "Q.931 Segments", "q931.segments",
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FT_NONE, BASE_NONE, NULL, 0x0,
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"Q.931 Segments"}
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},
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{ &hf_q931_reassembled_in,
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{ "Reassembled Q.931 in frame", "q931.reassembled_in",
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FT_FRAMENUM, BASE_NONE, NULL, 0x0,
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"This Q.931 message is reassembled in this frame"}
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},
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};
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static gint *ett[] = {
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&ett_q931,
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&ett_q931_ie,
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&ett_q931_segments,
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&ett_q931_segment,
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};
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module_t *q931_module;
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proto_q931 = proto_register_protocol("Q.931", "Q.931", "q931");
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proto_register_field_array (proto_q931, hf, array_length(hf));
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proto_register_subtree_array(ett, array_length(ett));
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register_init_routine(q931_init);
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register_dissector("q931", dissect_q931, proto_q931);
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q931_tpkt_pdu_handle = create_dissector_handle(dissect_q931_tpkt_pdu,
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@ -2946,6 +3098,10 @@ proto_register_q931(void)
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"Desegment all Q.931 messages spanning multiple TCP segments",
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"Whether the Q.931 dissector should desegment all messages spanning multiple TCP segments",
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&q931_desegment);
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prefs_register_bool_preference(q931_module, "reassembly",
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"Reassembly segmented Q.931 messages",
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"Reassembly segmented Q.931 messages (Q.931 - Annex H)",
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&q931_reassembly);
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}
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void
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